James Gain

Contact information

Email: jgain[at]cs[dot]uct[dot]ac[dot]za
Tel: +27-(0)21-650 4058
Fax: +27-(0)21-650 3551
Room 314 Computer Science Building
Department of Computer Science
University of Cape Town
7700 Rondebosch, Cape Town, South Africa

Teaching

Summer 2020: Virtual reality
Fall 2019: 3D geometry for computer graphics

Students and postdocs

Konrad Kapp, Johan Bontes, Paul Wanjohi, Tashiv Sewpersad, Stephan Finniss, Erin Versfeld.

Alumni

Timothy Gwynn, Ulysse Vimont, Hendranus Vermeulen, Benjamin Hugo, Harry Long, Kwegyir Lwabona, Ryan Mazzolini, Shaun Silson, Jonathan van Belle, Chen Wei, Bruce Merry, Justin Crause, Tsu-Shiuan Lin, Sunrise Wang, Duncan Clough, Julian Kenwood, Simon Perkins, Zacharia Crumley, Ian Tunbridge, Flora Tasse, Cara Winterbottom, Johannes Jansen van Vuuren, James Lane, Carl Hultquist, David Jacka, Ashley Reid, Gerrit Greef, Christopher de Kast, Rudolph Neeser, Solomon Bhunu, Barry Steyn

 

I am a Professor in the Department of Computer Science at the University of Cape Town and a member of its Collaborative Visual Computing (CVC) and High-Performance Computing (HPC) Laboratories.
My interest lie in the areas of Computer Graphics (specifically geometry and modelling) and Virtual Reality. My research takes place as part of the CVC group at UCT.

Projects

Authoring Digital Landscapes

Simulated natural phenomena, encompassing terrain, river networks, ecosystems, and weather effects are an essential feature in many games, films, and virtual environments. My research in this area is focused on the trifecta of visual realism, computational efficiency and authoring control. This is achieved through a mix of procedural, simulation and data-driven approaches and coupled with sketching and painting interfaces.

 

Interaction in Virtual Reality

The output side of Virtual Reality, in the form of Head Mounted Displays, is highly effective, but the input side, typically using hand-held controllers, is less mature. My focus here is on exploiting the sense of touch (haptics) to enhance task performance and immersion, while reducing simulator sickness. More generally, I am also interested in the application of Virtual Reality to scientific visualisation and design tasks.

 
 
 

Publications

[PDF] [VIDEO] [DOI] The Case for Haptic Props: Shape, Weight and Vibro-Tactile Feedback
M. White, J. Gain, U. Vimont, and D. Lochner
in Motion, Interaction and Games, New York, NY, USA, 2019.
[Bibtex]

@inproceedings{White2019,
author = {White, Michael and Gain, James and Vimont, Ulysse and Lochner, Daniel},
title = {The Case for Haptic Props: Shape, Weight and Vibro-Tactile Feedback},
year = {2019},
isbn = {9781450369947},
video = {https://youtu.be/pzUmK3jzcfk},
publisher = {Association for Computing Machinery},
address = {New York, NY, USA},
url = {https://doi.org/10.1145/3359566.3360058},
doi = {10.1145/3359566.3360058},
booktitle = {Motion, Interaction and Games},
articleno = {Article 7},
numpages = {10},
keywords = {Virtual Reality, Haptics, Game Experience},
location = {Newcastle upon Tyne, United Kingdom},
series = {MIG ’19}
}

[PDF] [VIDEO] [DOI] Procedural Riverscapes
A. Peytavie, T. Dupont, E. Guérin, Y. Cortial, B. Benes, J. Gain, and E. Galin
Computer Graphics Forum, vol. 38, iss. 7, pp. 35-46, 2019.
[Bibtex]

@article{Peytavie2019,
author = {Peytavie, A. and Dupont, T. and Guérin, E. and Cortial, Y. and Benes, B. and Gain, J. and Galin, E.},
title = {Procedural Riverscapes},
journal = {Computer Graphics Forum},
volume = {38},
number = {7},
video = {https://youtu.be/Xe2bjYaPMfY},
pages = {35-46},
doi = {10.1111/cgf.13814},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/cgf.13814},
eprint = {https://onlinelibrary.wiley.com/doi/pdf/10.1111/cgf.13814},
abstract = {Abstract This paper addresses the problem of creating animated riverscapes through a novel procedural framework that generates the inscribing geometry of a river network and then synthesizes matching real-time water movement animation. Our approach takes bare-earth heightfields as input, derives hydrologically-inspired river network trajectories, carves riverbeds into the terrain, and then automatically generates a corresponding blend-flow tree for the water surface. Characteristics, such as the riverbed width, depth and shape, as well as elevation and flow of the fluid surface, are procedurally derived from the terrain and river type. The riverbed is inscribed by combining compactly supported elevation modifiers over the river course. Subsequently, the water surface is defined as a time-varying continuous function encoded as a blend-flow tree with leaves that are parameterized procedural flow primitives and internal nodes that are blend operators. While river generation is fully automated, we also incorporate intuitive interactive editing of both river trajectories and individual riverbed and flow primitives. The resulting framework enables the generation of a wide range of river forms, ranging from slow meandering rivers to rapids with churning water, including surface effects, such as foam and leaves carried downstream.},
year = {2019}
}

[PDF] [VIDEO] [DOI] Orometry-Based Terrain Analysis and Synthesis
O. Argudo, E. Galin, A. Peytavie, A. Paris, J. Gain, and E. Guérin
ACM Trans. Graph., vol. 38, iss. 6, 2019.
[Bibtex]

@article{Argudo2019,
author = {Argudo, Oscar and Galin, Eric and Peytavie, Adrien and Paris, Axel and Gain, James and Gu\'{e}rin, Eric},
title = {Orometry-Based Terrain Analysis and Synthesis},
year = {2019},
issue_date = {November 2019},
publisher = {Association for Computing Machinery},
address = {New York, NY, USA},
volume = {38},
number = {6},
video = {https://youtu.be/-hjl8F_t7e0},
issn = {0730-0301},
url = {https://doi.org/10.1145/3355089.3356535},
doi = {10.1145/3355089.3356535},
journal = {ACM Trans. Graph.},
month = nov,
articleno = {Article 199},
numpages = {12},
keywords = {procedural modeling, terrain generation}
}

[PDF] [VIDEO] [DOI] Terrain Amplification with Implicit 3D Features
A. Paris, E. Galin, A. Peytavie, E. Guérin, and J. Gain
ACM Trans. Graph., vol. 38, iss. 5, 2019.
[Bibtex]

@article{Paris2019,
author = {Paris, Axel and Galin, Eric and Peytavie, Adrien and Gu\'{e}rin, Eric and Gain, James},
title = {Terrain Amplification with Implicit 3D Features},
year = {2019},
issue_date = {November 2019},
publisher = {Association for Computing Machinery},
address = {New York, NY, USA},
volume = {38},
video = {https://youtu.be/cRHLy_5wXJI},
number = {5},
issn = {0730-0301},
url = {https://doi.org/10.1145/3342765},
doi = {10.1145/3342765},
journal = {ACM Trans. Graph.},
month = sep,
articleno = {Article 147},
numpages = {15},
keywords = {implicit surfaces, Procedural modeling, landscapes}
}

[PDF] [DOI] A Review of Digital Terrain Modeling
E. Galin, E. Guérin, A. Peytavie, G. Cordonnier, M. Cani, B. Benes, and J. Gain
Computer Graphics Forum, vol. 38, iss. 2, pp. 553-577, 2019.
[Bibtex]

@article{Galin2019,
author = {Galin, Eric and Guérin, Eric and Peytavie, Adrien and Cordonnier, Guillaume and Cani, Marie-Paule and Benes, Bedrich and Gain, James},
title = {A Review of Digital Terrain Modeling},
journal = {Computer Graphics Forum},
volume = {38},
number = {2},
pages = {553-577},
keywords = {Categories and Subject Descriptors (according to ACM CCS): Shape Modeling Computer Graphics: —},
doi = {10.1111/cgf.13657},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/cgf.13657},
eprint = {https://onlinelibrary.wiley.com/doi/pdf/10.1111/cgf.13657},
abstract = {Abstract Terrains are a crucial component of three-dimensional scenes and are present in many Computer Graphics applications. Terrain modeling methods focus on capturing landforms in all their intricate detail, including eroded valleys arising from the interplay of varied phenomena, dendritic mountain ranges, and complex river networks. Set against this visual complexity is the need for user control over terrain features, without which designers are unable to adequately express their artistic intent. This article provides an overview of current terrain modeling and authoring techniques, organized according to three categories: procedural modeling, physically-based simulation of erosion and land formation processes, and example-based methods driven by scanned terrain data. We compare and contrast these techniques according to several criteria, specifically: the variety of achievable landforms; realism from both a perceptual and geomorphological perspective; issues of scale in terms of terrain extent and sampling precision; the different interaction metaphors and attendant forms of user-control, and computation and memory performance. We conclude with an in-depth discussion of possible research directions and outstanding technical and scientific challenges.},
year = {2019}
}

[PDF] [VIDEO] [DOI] Accurate Synthesis of Multi-Class Disk Distributions
P. Ecormier-Nocca, P. Memari, J. Gain, and M. Cani
Computer Graphics Forum, vol. 38, iss. 2, pp. 157-168, 2019.
[Bibtex]

@article{Ecormier-Nocca2019,
author = {Ecormier-Nocca, Pierre and Memari, Pooran and Gain, James and Cani, Marie-Paule},
title = {Accurate Synthesis of Multi-Class Disk Distributions},
journal = {Computer Graphics Forum},
volume = {38},
number = {2},
pages = {157-168},
keywords = {CCS Concepts, • Theory of computation → Randomness, geometry and discrete structures, • Computing methodologies → Shape modeling},
doi = {10.1111/cgf.13627},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/cgf.13627},
eprint = {https://onlinelibrary.wiley.com/doi/pdf/10.1111/cgf.13627},
abstract = {Abstract While analysing and synthesising 2D distributions of points has been applied both to the generation of textures with discrete elements and for populating virtual worlds with 3D objects, the results are often inaccurate since the spatial extent of objects cannot be expressed. We introduce three improvements enabling the synthesis of more general distributions of elements. First, we extend continuous pair correlation function (PCF) algorithms to multi-class distributions using a dependency graph, thereby capturing interrelationships between distinct categories of objects. Second, we introduce a new normalised metric for disks, which makes the method applicable to both point and possibly overlapping disk distributions. The metric is specifically designed to distinguish perceptually salient features, such as disjoint, tangent, overlapping, or nested disks. Finally, we pay particular attention to convergence of the mean PCF as well as the validity of individual PCFs, by taking into consideration the variance of the input. Our results demonstrate that this framework can capture and reproduce real-life distributions of elements representing a variety of complex semi-structured patterns, from the interaction between trees and the understorey in a forest to droplets of water. More generally, it applies to any category of 2D object whose shape is better represented by bounding circles than points.},
year = {2019}
}

[PDF] [DOI] A Survey of Augmented, Virtual, and Mixed Reality for Cultural Heritage
M. K. Bekele, R. Pierdicca, E. Frontoni, E. S. Malinverni, and J. Gain
J. Comput. Cult. Herit., vol. 11, iss. 2, 2018.
[Bibtex]

@article{Bekele2018,
author = {Bekele, Mafkereseb Kassahun and Pierdicca, Roberto and Frontoni, Emanuele and Malinverni, Eva Savina and Gain, James},
title = {A Survey of Augmented, Virtual, and Mixed Reality for Cultural Heritage},
year = {2018},
issue_date = {June 2018},
publisher = {Association for Computing Machinery},
address = {New York, NY, USA},
volume = {11},
number = {2},
issn = {1556-4673},
url = {https://doi.org/10.1145/3145534},
doi = {10.1145/3145534},
journal = {J. Comput. Cult. Herit.},
month = mar,
articleno = {Article 7},
numpages = {36},
keywords = {mixed reality, Cultural heritage, augmented reality, virtual reality}
}

[PDF] [DOI] Interactive Generation of Time-evolving, Snow-Covered Landscapes with Avalanches
G. Cordonnier, P. Ecormier, E. Galin, J. Gain, B. Benes, and M. -P. Cani
Computer Graphics Forum, vol. 37, iss. 2, pp. 497-509, 2018.
[Bibtex]

@article{Cordonnier2018,
author = {Cordonnier, G. and Ecormier, P. and Galin, E. and Gain, J. and Benes, B. and Cani, M.-P.},
title = {Interactive Generation of Time-evolving, Snow-Covered Landscapes with Avalanches},
journal = {Computer Graphics Forum},
volume = {37},
number = {2},
pages = {497-509},
keywords = {CCS Concepts, Computing methodologies → Shape modeling, Human-centered computing → Interaction techniques},
doi = {10.1111/cgf.13379},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/cgf.13379},
eprint = {https://onlinelibrary.wiley.com/doi/pdf/10.1111/cgf.13379},
abstract = {Abstract We introduce a novel method for interactive generation of visually consistent, snow-covered landscapes and provide control of their dynamic evolution over time. Our main contribution is the real-time phenomenological simulation of avalanches and other user-guided events, such as tracks left by Nordic skiing, which can be applied to interactively sculpt the landscape. The terrain is modeled as a height field with additional layers for stable, compacted, unstable, and powdery snow, which behave in combination as a semi-viscous fluid. We incorporate the impact of several phenomena, including sunlight, temperature, prevailing wind direction, and skiing activities. The snow evolution includes snow-melt and snow-drift, which affect stability of the snow mass and the probability of avalanches. A user can shape landscapes and their evolution either with a variety of interactive brushes, or by prescribing events along a winter season time-line. Our optimized GPU-implementation allows interactive updates of snow type and depth across a large (10 × 10 km) terrain, including real-time avalanches, making this suitable for visual assets in computer games. We evaluate our method through perceptual comparison against exiting methods and real snow-depth data.},
year = {2018}
}

[PDF] [DOI] Accelerated Deconvolution of Radio Interferometric Images using Orthogonal Matching Pursuit and Graphics Hardware
J. Van Belle, R. Armstrong, and J. Gain
Journal of Astronomical Instrumentation, vol. 06, iss. 04, p. 1750009, 2017.
[Bibtex]

@article{VanBelle2017,
author = {Van Belle, Jonathan and Armstrong, Richard and Gain, James},
title = {Accelerated Deconvolution of Radio Interferometric Images using Orthogonal Matching Pursuit and Graphics Hardware},
journal = {Journal of Astronomical Instrumentation},
volume = {06},
number = {04},
pages = {1750009},
year = {2017},
doi = {10.1142/S225117171750009X},
URL = { https://doi.org/10.1142/S225117171750009X},
eprint = {https://doi.org/10.1142/S225117171750009X},
abstract = { Deconvolution of native radio interferometric images constitutes a major computational component of the imaging process. An efficient and robust deconvolution operation is essential for reconstruction of the true sky signal from measured telescopic data. The techniques of compressed sensing provide a mathematically-rigorous framework within which to implement deconvolution of images formed from a sparse set of nearly-random measurements. We present an accelerated implementation of the orthogonal matching pursuit (OMP) algorithm (a compressed sensing method) that makes use of graphics processing unit (GPU) hardware. We show that OMP correctly identifies more sources than CLEAN, identifying up to 82\% of the sources in 100 test images, while CLEAN only identifies up to 61\% of the sources. In addition, the residual after source extraction is 2.7 times lower for OMP than for CLEAN. Furthermore, the graphics implementation of OMP performs around 23 times faster than a 4-core CPU. }
}

[PDF] [VIDEO] [DOI] Authoring Landscapes by Combining Ecosystem and Terrain Erosion Simulation
G. Cordonnier, E. Galin, J. Gain, B. Benes, E. Guérin, A. Peytavie, and M. Cani
ACM Trans. Graph., vol. 36, iss. 4, 2017.
[Bibtex]

@article{Cordonnier2017,
author = {Cordonnier, Guillaume and Galin, Eric and Gain, James and Benes, Bedrich and Gu\'{e}rin, Eric and Peytavie, Adrien and Cani, Marie-Paule},
title = {Authoring Landscapes by Combining Ecosystem and Terrain Erosion Simulation},
year = {2017},
issue_date = {July 2017},
publisher = {Association for Computing Machinery},
address = {New York, NY, USA},
volume = {36},
number = {4},
video ={https://youtu.be/9NXL48-Fbb8},
issn = {0730-0301},
url = {https://doi.org/10.1145/3072959.3073667},
doi = {10.1145/3072959.3073667},
journal = {ACM Trans. Graph.},
month = jul,
articleno = {Article 134},
numpages = {12},
keywords = {erosion, stochastic, simulation of natural phenomena, vegetation, landscape, terrain}
}

[PDF] [DOI] EcoBrush: Interactive Control of Visually Consistent Large-Scale Ecosystems
J. Gain, H. Long, G. Cordonnier, and M. -P. Cani
Computer Graphics Forum, vol. 36, iss. 2, pp. 63-73, 2017.
[Bibtex]

@article{Gain2017,
author = {Gain, J. and Long, H. and Cordonnier, G. and Cani, M.-P.},
title = {EcoBrush: Interactive Control of Visually Consistent Large-Scale Ecosystems},
journal = {Computer Graphics Forum},
volume = {36},
number = {2},
pages = {63-73},
keywords = {Categories and Subject Descriptors (according to ACM CCS), 1.3.7 Computer Graphics: Three-dimensional graphics and realism—},
doi = {10.1111/cgf.13107},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/cgf.13107},
eprint = {https://onlinelibrary.wiley.com/doi/pdf/10.1111/cgf.13107},
abstract = {Abstract One challenge in portraying large-scale natural scenes in virtual environments is specifying the attributes of plants, such as species, size and placement, in a way that respects the features of natural ecosystems, while remaining computationally tractable and allowing user design. To address this, we combine ecosystem simulation with a distribution analysis of the resulting plant attributes to create biome-specific databases, indexed by terrain conditions, such as temperature, rainfall, sunlight and slope. For a specific terrain, interpolated entries are drawn from this database and used to interactively synthesize a full ecosystem, while retaining the fidelity of the original simulations. A painting interface supplies users with semantic brushes for locally adjusting ecosystem age, plant density and variability, as well as optionally picking from a palette of precomputed distributions. Since these brushes are keyed to the underlying terrain properties a balance between user control and real-world consistency is maintained. Our system can be be used to interactively design ecosystems up to 5 × 5 km2 in extent, or to automatically generate even larger ecosystems in a fraction of the time of a full simulation, while demonstrating known properties from plant ecology such as succession, self-thinning, and underbrush, across a variety of biomes.},
year = {2017}
}

[PDF] [DOI] Reimagining Gamification through the Lens of Activity Theory
H. Vermeulen, J. Gain, P. Marais, and S. ODonovan
in 2016 49th Hawaii International Conference on System Sciences (HICSS), 2016, pp. 1328-1337.
[Bibtex]

@inproceedings{Vermeulen2016,
author={H. {Vermeulen} and J. {Gain} and P. {Marais} and S. {ODonovan}},
booktitle={2016 49th Hawaii International Conference on System Sciences (HICSS)},
title={Reimagining Gamification through the Lens of Activity Theory},
year={2016},
doi={10.1109/HICSS.2016.168},
volume={},
number={},
pages={1328-1337}
}

[PDF] [DOI] Usability and Performance of Mouse-Based Rotation Controllers
S. Rybicki, B. DeRenzi, and J. Gain
in Proceedings of the 42nd Graphics Interface Conference, Waterloo, CAN, 2016, p. 93–100.
[Bibtex]

@inproceedings{Rybicki2016,
author = {Rybicki, Steven and DeRenzi, Brian and Gain, James},
title = {Usability and Performance of Mouse-Based Rotation Controllers},
year = {2016},
isbn = {9780994786814},
publisher = {Canadian Human-Computer Communications Society},
address = {Waterloo, CAN},
booktitle = {Proceedings of the 42nd Graphics Interface Conference},
pages = {93–100},
doi={10.20380/GI2016.12},
numpages = {8},
keywords = {Arcball, 3D User Interfaces, Discrete sliders, Two-Axis Valuator, 3D object manipulation, Usability, 3D Rotation},
location = {Victoria, British Columbia, Canada},
series = {GI ’16}
}

[PDF] [DOI] A Comparison of Interactive Shadows and Multi-View Layouts for Mouse-Based 3D Modelling
S. O’Donovan, J. Gain, and B. DeRenzi
in Proceedings of the Annual Conference of the South African Institute of Computer Scientists and Information Technologists, New York, NY, USA, 2016.
[Bibtex]

@inproceedings{Odonovan2016,
author = {O’Donovan, Siobhan and Gain, James and DeRenzi, Brian},
title = {A Comparison of Interactive Shadows and Multi-View Layouts for Mouse-Based 3D Modelling},
year = {2016},
isbn = {9781450348058},
publisher = {Association for Computing Machinery},
address = {New York, NY, USA},
url = {https://doi.org/10.1145/2987491.2987531},
doi = {10.1145/2987491.2987531},
booktitle = {Proceedings of the Annual Conference of the South African Institute of Computer Scientists and Information Technologists},
articleno = {Article 31},
numpages = {10},
keywords = {Direct Manipulation, 3D User Interfaces, Interactive Shadows, Quantitative User Studies, 3D Widgets, Human Computer Interaction},
location = {Johannesburg, South Africa},
series = {SAICSIT ’16}
}

[DOI] Parallel, Realistic and Controllable Terrain Synthesis
J. Gain, B. Merry, and P. Marais
Computer Graphics Forum, vol. 34, iss. 2, pp. 105-116, 2015.
[Bibtex]

@article{Gain2015,
author = {Gain, J. and Merry, B. and Marais, P.},
title = {Parallel, Realistic and Controllable Terrain Synthesis},
journal = {Computer Graphics Forum},
volume = {34},
number = {2},
pages = {105-116},
keywords = {Categories and Subject Descriptors (according to ACM CCS), I.3.3 Computer Graphics: Three-Dimensional Graphics and Realism—Texture},
doi = {10.1111/cgf.12545},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/cgf.12545},
eprint = {https://onlinelibrary.wiley.com/doi/pdf/10.1111/cgf.12545},
year = {2015}
}

[PDF] [DOI] Controlling Crowd Simulations Using Neuro-Evolution
S. Wang, J. E. Gain, and G. S. Nistchke
in Proceedings of the 2015 Annual Conference on Genetic and Evolutionary Computation, New York, NY, USA, 2015, p. 353–360.
[Bibtex]

@inproceedings{Wang2015,
author = {Wang, Sunrise and Gain, James Edward and Nistchke, Geoff Stuart},
title = {Controlling Crowd Simulations Using Neuro-Evolution},
year = {2015},
isbn = {9781450334723},
publisher = {Association for Computing Machinery},
address = {New York, NY, USA},
url = {https://doi.org/10.1145/2739480.2754715},
doi = {10.1145/2739480.2754715},
booktitle = {Proceedings of the 2015 Annual Conference on Genetic and Evolutionary Computation},
pages = {353–360},
numpages = {8},
keywords = {neural networks, entertainment and media, simulation optimization, genetic algorithms, multi-agent systems},
location = {Madrid, Spain},
series = {GECCO ’15}
}

[PDF] [DOI] Moving Least-Squares Reconstruction of Large Models with GPUs
B. Merry, J. Gain, and P. Marais
IEEE Transactions on Visualization and Computer Graphics, vol. 20, iss. 2, pp. 249-261, 2014.
[Bibtex]

@article{Merry2014,
author={B. {Merry} and J. {Gain} and P. {Marais}},
journal={IEEE Transactions on Visualization and Computer Graphics},
title={Moving Least-Squares Reconstruction of Large Models with GPUs},
year={2014},
volume={20},
doi={10.1109/TVCG.2013.118},
number={2},
pages={249-261}
}

[PDF] Skywriter: Drawing Curves from a First-Person Perspective
S. Rybicki and J. Gain
in Proceedings of SAICSIT 2014, 2014, pp. 1-4.
[Bibtex]

@inproceedings{Rybicki2014,
author={Rybicki, Steven and Gain, James},
title={Skywriter: Drawing Curves from a First-Person Perspective},
year={2014},
booktitle={Proceedings of SAICSIT 2014},
location={Centurion, Gauteng, South Africa},
pages={1-4},
series={SAICSIT '14}
}

[PDF] [DOI] Comparing crossover operators in Neuro-Evolution with crowd simulations
S. Wang, J. Gain, and G. Nitschke
in 2014 IEEE Congress on Evolutionary Computation (CEC), 2014, pp. 2298-2305.
[Bibtex]

@inproceedings{Wang2014,
author={S. {Wang} and J. {Gain} and G. {Nitschke}},
booktitle={2014 IEEE Congress on Evolutionary Computation (CEC)},
title={Comparing crossover operators in Neuro-Evolution with crowd simulations},
doi={10.1109/cec.2014.6900483},
year={2014},
pages={2298-2305}
}

[PDF] City Sketching
J. Gain, P. Marais, and R. Neeser
Journal of WSCG, vol. 22, iss. 1, pp. 1-10, 2014.
[Bibtex]

@article{Gain2014,
author={Gain, James and Marais, Patrick and Neeser, Rudy},
year={2014},
title={City Sketching},
journal={Journal of WSCG},
volume={22},
number={1},
pages={1-10}
}

[PDF] Efficient Procedural Generation of Forests
J. Kenwood, J. Gain, and P. Marais
Journal of WSCG, vol. 22, iss. 1, pp. 31-38, 2014.
[Bibtex]

@article{Kenwood2014,
author={Kenwood, Julian and Gain, James and Marais, Patrick},
year={2014},
title={Efficient Procedural Generation of Forests},
journal={Journal of WSCG},
volume={22},
number={1},
pages={31-38}
}

[PDF] [DOI] Fast In-Place Binning of Laser Range-Scanned Point Sets
B. Merry, J. Gain, and P. Marais
J. Comput. Cult. Herit., vol. 6, iss. 3, 2013.
[Bibtex]

@article{Merry2013a,
author = {Merry, Bruce and Gain, James and Marais, Patrick},
title = {Fast In-Place Binning of Laser Range-Scanned Point Sets},
year = {2013},
issue_date = {July 2013},
publisher = {Association for Computing Machinery},
address = {New York, NY, USA},
volume = {6},
number = {3},
issn = {1556-4673},
url = {10.1145/2499931.2499935},
doi = {10.1145/2499931.2499935},
journal = {J. Comput. Cult. Herit.},
month = aug,
articleno = {Article 14},
numpages = {19},
keywords = {point cloud, octree, Binning, out-of-core}
}

[PDF] [DOI] Field D* Path-finding on Weighted Triangulated and Tetrahedral Meshes
S. Perkins, P. Marais, J. Gain, and M. Berman
Autonomous Agents and Multi-Agent Systems, vol. 26, iss. 3, p. 354–388, 2013.
[Bibtex]

@article{Perkins2013,
author = {Perkins, Simon and Marais, Patrick and Gain, James and Berman, Mark},
title = {Field D* Path-finding on Weighted Triangulated and Tetrahedral Meshes},
journal = {Autonomous Agents and Multi-Agent Systems},
volume = {26},
number = {3},
doi={10.1007/s10458-012-9195-8},
pages = {354–388},
year = {2013}
}

[PDF] [DOI] A Case Study in the Gamification of a University-Level Games Development Course
S. O’Donovan, J. Gain, and P. Marais
in Proceedings of the South African Institute for Computer Scientists and Information Technologists Conference, New York, NY, USA, 2013, p. 242–251.
[Bibtex]

@inproceedings{ODonovan2013,
author = {O’Donovan, Siobhan and Gain, James and Marais, Patrick},
title = {A Case Study in the Gamification of a University-Level Games Development Course},
year = {2013},
isbn = {9781450321129},
publisher = {Association for Computing Machinery},
address = {New York, NY, USA},
url = {https://doi.org/10.1145/2513456.2513469},
doi = {10.1145/2513456.2513469},
booktitle = {Proceedings of the South African Institute for Computer Scientists and Information Technologists Conference},
pages = {242–251},
numpages = {10},
keywords = {gamification, games design, active learning},
location = {East London, South Africa},
series = {SAICSIT ’13}
}

[PDF] [DOI] Using Poll Sheets and Computer Vision as an Inexpensive Alternative to Clickers
J. Gain
in Proceedings of the South African Institute for Computer Scientists and Information Technologists Conference, New York, NY, USA, 2013, pp. 60-63.
[Bibtex]

@inproceedings{Gain2013,
author = {Gain, James},
title = {Using Poll Sheets and Computer Vision as an Inexpensive Alternative to Clickers},
year = {2013},
isbn = {9781450321129},
publisher = {Association for Computing Machinery},
address = {New York, NY, USA},
url = {https://doi.org/10.1145/2513456.2513469},
doi = {10.1145/2513456.2513469},
booktitle = {Proceedings of the South African Institute for Computer Scientists and Information Technologists Conference},
pages = {60-63},
numpages = {4},
location = {East London, South Africa},
series = {SAICSIT ’13}
}

[PDF] [DOI] Accelerating kd-tree Searches for all k-nearest Neighbours
B. Merry, J. Gain, and P. Marais
in Eurographics 2013 – Short Papers, 2013, pp. 37-40.
[Bibtex]

@inproceedings{Merry2013b,
author = {Merry, Bruce and Gain, James and Marais, Patrick},
title = {Accelerating kd-tree Searches for all k-nearest Neighbours},
booktitle = {Eurographics 2013 – Short Papers},
location = {Girona, Spain},
doi={10.2312/conf/EG2013/short/037-040},
year = {2013},
publisher = {Eurographics Association},
pages = {37-40},
}

[PDF] [DOI] Efficient compression of molecular dynamics trajectory files
P. Marais, J. Kenwood, K. C. Smith, M. M. Kuttel, and J. Gain
Journal of Computational Chemistry, vol. 33, iss. 27, pp. 2131-2141, 2012.
[Bibtex]

@article{Marais2012,
author = {Marais, Patrick and Kenwood, Julian and Smith, Keegan Carruthers and Kuttel, Michelle M. and Gain, James},
title = {Efficient compression of molecular dynamics trajectory files},
journal = {Journal of Computational Chemistry},
volume = {33},
number = {27},
pages = {2131-2141},
keywords = {Keywords: MD trajectory files, compression, arithmetic coding, interframe prediction},
doi = {10.1002/jcc.23050},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/jcc.23050},
eprint = {https://onlinelibrary.wiley.com/doi/pdf/10.1002/jcc.23050},
abstract = {Abstract We investigate whether specific properties of molecular dynamics trajectory files can be exploited to achieve effective file compression. We explore two classes of lossy, quantized compression scheme: “interframe” predictors, which exploit temporal coherence between successive frames in a simulation, and more complex “intraframe” schemes, which compress each frame independently. Our interframe predictors are fast, memory-efficient and well suited to on-the-fly compression of massive simulation data sets, and significantly outperform the benchmark BZip2 application. Our schemes are configurable: atomic positional accuracy can be sacrificed to achieve greater compression. For high fidelity compression, our linear interframe predictor gives the best results at very little computational cost: at moderate levels of approximation (12-bit quantization, maximum error ≈ 10−2 Å), we can compress a 1–2 fs trajectory file to 5–8\% of its original size. For 200 fs time steps—typically used in fine grained water diffusion experiments—we can compress files to ∼25\% of their input size, still substantially better than BZip2. While compression performance degrades with high levels of quantization, the simulation error is typically much greater than the associated approximation error in such cases.},
year = {2012}
}

[PDF] [DOI] Enhanced Texture-Based Terrain Synthesis on Graphics Hardware
F. Tasse, J. Gain, and P. Marais
Computer Graphics Forum, vol. 31, iss. 6, pp. 1959-1972, 2012.
[Bibtex]

@article{Tasse2012,
author = {Tasse, Flora and Gain, James and Marais, Patrick},
title = {Enhanced Texture-Based Terrain Synthesis on Graphics Hardware},
journal = {Computer Graphics Forum},
volume = {31},
number = {6},
pages = {1959-1972},
keywords = {terrain generation, patch-based texture synthesis, terrain sketching, seam removal, patch merging, GPU, I.3.7 Computer Graphics: Three-Dimensional Graphics and Realism—Colour, shading, shadowing and texture},
doi = {10.1111/j.1467-8659.2012.03076.x},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1467-8659.2012.03076.x},
eprint = {https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1467-8659.2012.03076.x},
abstract = {Abstract Curvilinear features extracted from a 2D user-sketched feature map have been used successfully to constraint a patch-based texture synthesis of real landscapes. This map-based user interface does not give fine control over the height profile of the generated terrain. We propose a new texture-based terrain synthesis framework controllable by a terrain sketching interface. We enhance the realism of the generated landscapes by using a novel patch merging method that reduces boundary artefacts caused by overlapping terrain patches. A more constrained synthesis process is used to produce landscapes that better match user requirements. The high computational cost of texture synthesis is reduced with a parallel implementation on graphics hardware. Our GPU-accelerated solution provides a significant speedup depending on the size of the example terrain. We show experimentally that our framework is more successful in generating realistic landscapes than current example-based terrain synthesis methods. We conclude that texture-based terrain synthesis combined with sketching provides an excellent solution to the user control and realism challenges of virtual landscape generation.},
year = {2012}
}

[PDF] [VIDEO] Voxel-Space Shape Grammars
Z. Crumley, P. Marais, and J. Gain
in WSCG 2012: 20th International Conference on Computer Graphics, Visualization and Computer Vision, 2012, pp. 1-10.
[Bibtex]

@inproceedings{Crumley2012,
author = {Crumley, Zacharia and Marais, Patrick and Gain, James},
title = {Voxel-Space Shape Grammars},
booktitle = {WSCG 2012: 20th International Conference on Computer Graphics, Visualization and Computer Vision},
location = {Plzen, Czech Republic},
year = {2012},
pages = {1-10},
}

[PDF] [DOI] Simulation of Coarse-Grained Protein−Protein Interactions with Graphics Processing Units
I. Tunbridge, R. B. Best, J. Gain, and M. M. Kuttel
Journal of Chemical Theory and Computation, vol. 6, iss. 11, pp. 3588-3600, 2010.
[Bibtex]

@article{Tunbridge2010,
author = {Tunbridge, Ian and Best, Robert B. and Gain, James and Kuttel, Michelle M.},
title = {Simulation of Coarse-Grained Protein−Protein Interactions with Graphics Processing Units},
journal = {Journal of Chemical Theory and Computation},
volume = {6},
number = {11},
pages = {3588-3600},
year = {2010},
doi = {10.1021/ct1003884},
}

[PDF] [DOI] Simplifying Character Skins with Analytic Error Metrics
B. Merry, P. Marais, and J. Gain
Computer Graphics Forum, vol. 29, iss. 1, pp. 13-24, 2010.
[Bibtex]

@article{Merry2010,
author = {Merry, Bruce and Marais, Patrick and Gain, James},
title = {Simplifying Character Skins with Analytic Error Metrics},
journal = {Computer Graphics Forum},
volume = {29},
number = {1},
pages = {13-24},
keywords = {character animation, simplification, I.3.7 Computer Graphics: Three-Dimensional Graphics and Realism—Animation, I.3.5 Computer Graphics: Computational Geometry and Object Modeling—Geometric algorithms, languages and systems},
doi = {10.1111/j.1467-8659.2009.01543.x},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1467-8659.2009.01543.x},
eprint = {https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1467-8659.2009.01543.x},
abstract = {Abstract Traditionally, levels of detail (LOD) for animated characters are computed from a single pose. Later techniques refined this approach by considering a set of sample poses and evaluating a more representative error metric. A recent approach to the character animation problem, animation space, (AS) provides a framework for measuring error analytically. The work presented here uses the animation-space framework to derive two new techniques to improve the quality of LOD approximations. First, we use an animation-space distance metric within a progressive mesh-based LOD scheme, giving results that are reasonable across a range of poses, without requiring that the pose space be sampled. Second, we simplify individual vertices by reducing the number of bones that influence them, using a constrained least-squares optimization. This influence simplification is combined with the progressive mesh to form a single stream of simplifications. Influence simplification reduces the geometric error by up to an order of magnitude, and allows models to be simplified further than is possible with only a progressive mesh. Quantitative (geometric error metrics) and qualititative (user perceptual) experiments confirm that these new extensions provide significant improvements in quality over traditional, naïve simplification; and while there is naturally some impact on the speed of the off-line simplification process, it is not prohibitive.},
year = {2010}
}

[PDF] [DOI] Dynamic Load Balancing of Lattice Boltzmann Free-Surface Fluid Animations
A. Reid, J. Gain, and M. Kuttel
in Proceedings of the 7th International Conference on Computer Graphics, Virtual Reality, Visualisation and Interaction in Africa, New York, NY, USA, 2010, p. 91–100.
[Bibtex]

@inproceedings{Reid2010,
author = {Reid, Ashley and Gain, James and Kuttel, Michelle},
title = {Dynamic Load Balancing of Lattice Boltzmann Free-Surface Fluid Animations},
year = {2010},
isbn = {9781450301183},
publisher = {Association for Computing Machinery},
address = {New York, NY, USA},
url = {https://doi.org/10.1145/1811158.1811174},
doi = {10.1145/1811158.1811174},
booktitle = {Proceedings of the 7th International Conference on Computer Graphics, Virtual Reality, Visualisation and Interaction in Africa},
pages = {91–100},
numpages = {10},
location = {Franschhoek, South Africa},
series = {AFRIGRAPH ’10}
}

[PDF] [DOI] Visualization of Solution Sets from Automated Docking of Molecular Structures
J. Jansen van Vuuren, M. Kuttel, and J. Gain
in Proceedings of the 7th International Conference on Computer Graphics, Virtual Reality, Visualisation and Interaction in Africa, New York, NY, USA, 2010, p. 111–120.
[Bibtex]

@inproceedings{JansenVanVuuren2010,
author = {Jansen van Vuuren, Johannes and Kuttel, Michelle and Gain, James},
title = {Visualization of Solution Sets from Automated Docking of Molecular Structures},
year = {2010},
isbn = {9781450301183},
publisher = {Association for Computing Machinery},
address = {New York, NY, USA},
url = {https://doi.org/10.1145/1811158.1811177},
doi = {10.1145/1811158.1811177},
booktitle = {Proceedings of the 7th International Conference on Computer Graphics, Virtual Reality, Visualisation and Interaction in Africa},
pages = {111–120},
numpages = {10},
keywords = {molecular docking, multi-dimensional visualization, glyphs},
location = {Franschhoek, South Africa},
series = {AFRIGRAPH ’10}
}

[PDF] [DOI] Automatic Addition of Physics Components to Procedural Content
R. Baxter, Z. Crumley, R. Neeser, and J. Gain
in Proceedings of the 7th International Conference on Computer Graphics, Virtual Reality, Visualisation and Interaction in Africa, New York, NY, USA, 2010, p. 101–110.
[Bibtex]

@inproceedings{Baxter2010,
author = {Baxter, Richard and Crumley, Zacharia and Neeser, Rudolph and Gain, James},
title = {Automatic Addition of Physics Components to Procedural Content},
year = {2010},
isbn = {9781450301183},
publisher = {Association for Computing Machinery},
address = {New York, NY, USA},
url = {https://doi.org/10.1145/1811158.1811175},
doi = {10.1145/1811158.1811175},
booktitle = {Proceedings of the 7th International Conference on Computer Graphics, Virtual Reality, Visualisation and Interaction in Africa},
pages = {101–110},
numpages = {10},
keywords = {wall grammars, procedural generation, physics, dynamic animation, descriptive grammars, shape grammars, L-systems},
location = {Franschhoek, South Africa},
series = {AFRIGRAPH ’10}
}

[PDF] [DOI] An Adjectival Interface for Procedural Content Generation
C. Hultquist, J. Gain, and D. Cairns, in Intelligent Computer Graphics 2009, D. Plemenos and G. Miaoulis, Eds., Berlin, Heidelberg: Springer Berlin Heidelberg, 2009, p. 143–165.
[Bibtex]

@inbook{Hultquist2009,
author="Hultquist, Carl
and Gain, James
and Cairns, David",
editor="Plemenos, Dimitri
and Miaoulis, Georgios",
title="An Adjectival Interface for Procedural Content Generation",
bookTitle="Intelligent Computer Graphics 2009",
year="2009",
publisher="Springer Berlin Heidelberg",
address="Berlin, Heidelberg",
pages="143--165",
abstract="This paper presents a novel interface for generating procedural models, textures, and other content, motivated by the need for interfaces that are simpler to understand and more rapidly utilize. Instead of directly manipulating procedural parameters, users specify adjectives that describe the content to be generated. By making use of a training corpus and semantic information from the WordNet database, our system is able to map from the set of all possible descriptions, adjective space, to the set of all combinations of procedural parameters, parameter space. This is achieved through a modification to radial basis function networks, and the application of particle swarm optimisation to search for suitable solutions. By testing with three very different procedural generation systems, we demonstrate the wide applicability of this approach.Our results show that non-technical users not only prefer an adjectival interface to one offering direct control over the procedural parameters, but also produce content that more closely matches a given target.",
isbn="978-3-642-03452-7",
doi="10.1007/978-3-642-03452-7_8",
url="https://doi.org/10.1007/978-3-642-03452-7_8"
}

[PDF] [VIDEO] [DOI] Terrain Sketching
J. Gain, P. Marais, and W. Strasser
in Proceedings of the 2009 Symposium on Interactive 3D Graphics and Games, New York, NY, USA, 2009, p. 31–38.
[Bibtex]

@inproceedings{Gain2009,
author = {Gain, James and Marais, Patrick and Stra\sser, Wolfgang},
title = {Terrain Sketching},
year = {2009},
isbn = {9781605584294},
video = {https://youtu.be/JclodOVP0Tc},
publisher = {Association for Computing Machinery},
address = {New York, NY, USA},
url = {https://doi.org/10.1145/1507149.1507155},
doi = {10.1145/1507149.1507155},
booktitle = {Proceedings of the 2009 Symposium on Interactive 3D Graphics and Games},
pages = {31–38},
numpages = {8},
location = {Boston, Massachusetts},
series = {I3D ’09}
}

[PDF] [DOI] Revisiting District Six: A Case Study of Digital Heritage Reconstruction from Archival Photographs
C. de Kadt, J. Gain, and P. Marais
in Proceedings of the 6th International Conference on Computer Graphics, Virtual Reality, Visualisation and Interaction in Africa, New York, NY, USA, 2009, p. 13–21.
[Bibtex]

@inproceedings{DeKadt2009,
author = {de Kadt, Christopher and Gain, James and Marais, Patrick},
title = {Revisiting District Six: A Case Study of Digital Heritage Reconstruction from Archival Photographs},
year = {2009},
isbn = {9781605584287},
publisher = {Association for Computing Machinery},
address = {New York, NY, USA},
url = {https://doi.org/10.1145/1503454.1503457},
doi = {10.1145/1503454.1503457},
booktitle = {Proceedings of the 6th International Conference on Computer Graphics, Virtual Reality, Visualisation and Interaction in Africa},
pages = {13–21},
numpages = {9},
keywords = {heritage preservation, photogrammetric reconstruction, texture synthesis},
location = {Pretoria, South Africa},
series = {AFRIGRAPH ’09}
}

[PDF] [DOI] Analytic Simplification of Animated Characters
B. Merry, P. Marais, and J. Gain
in Proceedings of the 6th International Conference on Computer Graphics, Virtual Reality, Visualisation and Interaction in Africa, New York, NY, USA, 2009, p. 37–45.
[Bibtex]

@inproceedings{Merry2009,
author = {Merry, Bruce and Marais, Patrick and Gain, James},
title = {Analytic Simplification of Animated Characters},
year = {2009},
isbn = {9781605584287},
publisher = {Association for Computing Machinery},
address = {New York, NY, USA},
url = {https://doi.org/10.1145/1503454.1503462},
doi = {10.1145/1503454.1503462},
booktitle = {Proceedings of the 6th International Conference on Computer Graphics, Virtual Reality, Visualisation and Interaction in Africa},
pages = {37–45},
numpages = {9},
keywords = {simplification, character animation},
location = {Pretoria, South Africa},
series = {AFRIGRAPH ’09}
}

[PDF] [DOI] Visualisation of cyclic and multi-branched molecules with VMD
S. Cross, M. M. Kuttel, J. E. Stone, and J. E. Gain
Journal of Molecular Graphics and Modelling, vol. 28, iss. 2, pp. 131-139, 2009.
[Bibtex]

@article{Cross2009,
title = "Visualisation of cyclic and multi-branched molecules with VMD",
journal = "Journal of Molecular Graphics and Modelling",
volume = "28",
number = "2",
pages = "131 - 139",
year = "2009",
issn = "1093-3263",
doi = "https://doi.org/10.1016/j.jmgm.2009.04.010",
url = "http://www.sciencedirect.com/science/article/pii/S1093326309000527",
author = "Simon Cross and Michelle M. Kuttel and John E. Stone and James E. Gain",
keywords = "Carbohydrate, Polysaccharide, Molecular visualisation, Chitinases, Chitolectins, Oligosaccharides, VMD",
abstract = "We report the addition of two visualisation algorithms, termed PaperChain and Twister, to the freely available Visual Molecular Dynamics (VMD) package. These algorithms produce visualisations of complex cyclic molecules and multi-branched polysaccharides and are a generalization and optimization of those we previously developed in a standalone package for carbohydrates. PaperChain highlights each ring in a molecular structure with a polygon, which is coloured according to the ring pucker. Twister traces glycosidic bonds with a ribbon that twists according to the relative orientation of successive sugar residues. Combination of these novel algorithms and new ring selection statements with the large set of visualisations already available in VMD allows for unprecedented flexibility in the level of detail displayed for glycoconjugate, glycoprotein and carbohydrate-binding protein structures, as well as other cyclic structures. We highlight the efficacy of these algorithms with selected illustrative examples, clearly demonstrating the value of the new visualisations, not only for structure validation, but also for facilitating insights into molecular structure and mechanism."
}

[PDF] [DOI] Comparing the accuracy and precision of three techniques used for estimating missing landmarks when reconstructing fossil hominin crania
R. Neeser, R. R. Ackermann, and J. Gain
American Journal of Physical Anthropology, vol. 140, iss. 1, pp. 1-18, 2009.
[Bibtex]

@article{Neeser2009,
author = {Neeser, Rudolph and Ackermann, Rebecca Rogers and Gain, James},
title = {Comparing the accuracy and precision of three techniques used for estimating missing landmarks when reconstructing fossil hominin crania},
journal = {American Journal of Physical Anthropology},
volume = {140},
number = {1},
pages = {1-18},
keywords = {hominoids, estimation, mean substitution, thin plate splines, regression},
doi = {10.1002/ajpa.21023},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/ajpa.21023},
eprint = {https://onlinelibrary.wiley.com/doi/pdf/10.1002/ajpa.21023},
abstract = {Abstract Various methodological approaches have been used for reconstructing fossil hominin remains in order to increase sample sizes and to better understand morphological variation. Among these, morphometric quantitative techniques for reconstruction are increasingly common. Here we compare the accuracy of three approaches—mean substitution, thin plate splines, and multiple linear regression—for estimating missing landmarks of damaged fossil specimens. Comparisons are made varying the number of missing landmarks, sample sizes, and the reference species of the population used to perform the estimation. The testing is performed on landmark data from individuals of Homo sapiens, Pan troglodytes and Gorilla gorilla, and nine hominin fossil specimens. Results suggest that when a small, same-species fossil reference sample is available to guide reconstructions, thin plate spline approaches perform best. However, if no such sample is available (or if the species of the damaged individual is uncertain), estimates of missing morphology based on a single individual (or even a small sample) of close taxonomic affinity are less accurate than those based on a large sample of individuals drawn from more distantly related extant populations using a technique (such as a regression method) able to leverage the information (e.g., variation/covariation patterning) contained in this large sample. Thin plate splines also show an unexpectedly large amount of error in estimating landmarks, especially over large areas. Recommendations are made for estimating missing landmarks under various scenarios.},
year = {2009}
}

[PDF] [DOI] A Survey of Spatial Deformation from a User-Centered Perspective
J. Gain and D. Bechmann
ACM Trans. Graph., vol. 27, iss. 4, 2008.
[Bibtex]

@article{Gain2008,
author = {Gain, James and Bechmann, Dominique},
title = {A Survey of Spatial Deformation from a User-Centered Perspective},
year = {2008},
issue_date = {October 2008},
publisher = {Association for Computing Machinery},
address = {New York, NY, USA},
volume = {27},
number = {4},
issn = {0730-0301},
url = {https://doi.org/10.1145/1409625.1409629},
doi = {10.1145/1409625.1409629},
journal = {ACM Trans. Graph.},
month = nov,
articleno = {Article 107},
numpages = {21},
keywords = {warping, spatial deformation, Free-form deformation}
}

[PDF] Control Mechanisms for First Person Shooter Games on PDA
W. Chen, G. Marsden, and J. Gain
in Proceedings of OzCHI, 2008.
[Bibtex]

@inproceedings{Wei2008,
author = {Chen, Wei and Marsden, Gary and Gain, James},
title = {Control Mechanisms for First Person Shooter Games on PDA},
booktitle = {Proceedings of OzCHI},
year = {2008}
}

[PDF] [DOI] Particle swarm optimization with spatially meaningful neighbours
J. Lane, A. Engelbrecht, and J. Gain
in 2008 IEEE Swarm Intelligence Symposium, 2008, pp. 1-8.
[Bibtex]

@inproceedings{Lane2008,
author={James {Lane} and Andries {Engelbrecht} and James {Gain}},
booktitle={2008 IEEE Swarm Intelligence Symposium},
title={Particle swarm optimization with spatially meaningful neighbours},
year={2008},
volume={},
number={},
pages={1-8},
abstract={Neighbourhood topologies in particle swarm optimization (PSO) are typically random in terms of the spatial positions of connected neighbours. This study explores the use of spatially meaningful neighbours for PSO. An approach is designed which uses heuristics to leverage the natural neighbours computed with Delaunay triangulation. The approach is compared to standard PSO sociometries and fitness distance ratio approaches. Although intrinsic properties of Delaunay triangulation limit the practical application of this approach to low dimensions results show that it is a successful particle swarm optimizer.},
keywords={mesh generation;particle swarm optimisation;particle swarm optimization;Delaunay triangulation;fitness distance ratio approaches;Particle swarm optimization;Topology;Birds;Convergence;Computer science;USA Councils;Cities and towns;Africa;Cultural differences;Data structures;Delaunay Triangulation;Neighbour Topology;Particle Swarm Optimization;Heuristics},
doi={10.1109/SIS.2008.4668281},
ISSN={},
month={Sep.}
}

[PDF] [DOI] A Spatial Awareness Framework for Enhancing Game Agent Behaviour
S. Perkins, D. Jacka, J. Gain, and P. Marais
in Proceedings of the 2008 ACM SIGGRAPH Symposium on Video Games, New York, NY, USA, 2008, p. 15–22.
[Bibtex]

@inproceedings{Perkins2008,
author = {Perkins, Simon and Jacka, David and Gain, James and Marais, Patrick},
title = {A Spatial Awareness Framework for Enhancing Game Agent Behaviour},
year = {2008},
isbn = {9781605581736},
publisher = {Association for Computing Machinery},
address = {New York, NY, USA},
url = {https://doi.org/10.1145/1401843.1401846},
doi = {10.1145/1401843.1401846},
booktitle = {Proceedings of the 2008 ACM SIGGRAPH Symposium on Video Games},
pages = {15–22},
numpages = {8},
keywords = {games, spatial analysis, agents},
location = {Los Angeles, California},
series = {Sandbox ’08}
}

[PDF] [DOI] Distance-Ranked Connectivity Compression of Triangle Meshes
P. Marais, J. Gain, and D. Shreiner
Computer Graphics Forum, vol. 26, iss. 4, pp. 813-823, 2007.
[Bibtex]

@article{Marais2007,
author = {Marais, P. and Gain, J. and Shreiner, D.},
title = {Distance-Ranked Connectivity Compression of Triangle Meshes},
journal = {Computer Graphics Forum},
volume = {26},
number = {4},
pages = {813-823},
keywords = {geometric compression, connectivity, triangle prediction, I.3.m Computer Graphics: connectivity coding},
doi = {10.1111/j.1467-8659.2007.01026.x},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1467-8659.2007.01026.x},
eprint = {https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1467-8659.2007.01026.x},
abstract = {Abstract We present a new, single-rate method for compressing the connectivity information of a connected 2-manifold triangle mesh with or without boundary. Traditional compression schemes interleave geometry and connectivity coding, and are thus typically unable to utilize information from vertices (mesh regions) they have not yet processed. With the advent of competitive point cloud compression schemes, it has become feasible to develop separate connectivity encoding schemes that can exploit complete, global vertex position information to improve performance. Our scheme demonstrates the utility of this separation of vertex and connectivity coding. By traversing the mesh edges in a consistent fashion, and using global vertex information, we can predict the position of the vertex that completes the unprocessed triangle attached to a given edge. We then rank the vertices in the neighborhood of this predicted position by their Euclidean distance. The distance rank of the correct closing vertex is stored. Typically, these rank values are small, and the set of rank values thus possesses low entropy and compresses very well. The sequence of rank values is all that is required to represent the mesh connectivity—no special split or merge codes are necessary. Results indicate improvements over traditional valence-based schemes for more regular triangulations. Highly irregular triangulations or those containing a large number of slivers are not well modelled by our current set of predictors and may yield poorer connectivity compression rates than those provided by the best valence-based schemes.},
year = {2007}
}

[PDF] [DOI] A Comparison of Linear Skinning Techniques for Character Animation
D. Jacka, A. Reid, B. Merry, and J. Gain
, p. 177–186, 2007.
[Bibtex]

@article{Jacka2007,
author = {Jacka, David and Reid, Ashley and Merry, Bruce and Gain, James},
title = {A Comparison of Linear Skinning Techniques for Character Animation},
year = {2007},
isbn = {9781595939067},
publisher = {Association for Computing Machinery},
address = {New York, NY, USA},
url = {https://doi.org/10.1145/1294685.1294715},
doi = {10.1145/1294685.1294715},
booktitle = {Proceedings of the 5th International Conference on Computer Graphics, Virtual Reality, Visualisation and Interaction in Africa},
pages = {177–186},
numpages = {10},
keywords = {comparison, skinning, animation, real-time},
location = {Grahamstown, South Africa},
series = {AFRIGRAPH ’07}
}

[PDF] [DOI] Animation Space: A Truly Linear Framework for Character Animation
B. Merry, P. Marais, and J. Gain
ACM Trans. Graph., vol. 25, iss. 4, p. 1400–1423, 2006.
[Bibtex]

@article{Merry2006A,
author = {Merry, Bruce and Marais, Patrick and Gain, James},
title = {Animation Space: A Truly Linear Framework for Character Animation},
year = {2006},
issue_date = {October 2006},
publisher = {Association for Computing Machinery},
address = {New York, NY, USA},
volume = {25},
number = {4},
issn = {0730-0301},
url = {https://doi.org/10.1145/1183287.1183294},
doi = {10.1145/1183287.1183294},
journal = {ACM Trans. Graph.},
month = oct,
pages = {1400–1423},
numpages = {24},
keywords = {parametrization, Character animation, skinning}
}

[PDF] [DOI] Using Visualizations to Support Design and Debugging in Virtual Reality
C. Winterbottom, E. Blake, and J. Gain
in Advances in Visual Computing, Berlin, Heidelberg, 2006, p. 465–474.
[Bibtex]

@InProceedings{Winterbottom2006,
author="Winterbottom, Cara and Blake, Edwin and Gain, James",
title="Using Visualizations to Support Design and Debugging in Virtual Reality",
booktitle="Advances in Visual Computing",
year="2006",
publisher="Springer Berlin Heidelberg",
address="Berlin, Heidelberg",
pages="465--474",
doi={https://doi.org/10.1007/11919476_47},
abstract="We present a visualization system that helps designers conceptualise interactions in a virtual environment (VE). We use event-condition-action triads (triggersets) for specifying interactions, and provide multiple visualizations: sequence diagrams, floorplans and timelines. We present a two part study: sequencing VE interactions accurately and debugging mistakes. Subjects were divided into two groups: one received visualizations and triggersets and the other (a control group) received triggersets only. The visualization group described 72.5{\%} of the sequence correctly on average, compared to 56.4{\%} by the non-visualization group. The visualization group also detected more than twice as many errors as the control group. The visualization group worked well with multiple, linked windows to create an understanding of the design. Floorplans were most useful for an overview, timelines for understanding specific sequences and sequence diagrams for sequencing and finding mistakes.",
isbn="978-3-540-48631-2"
}

[PDF] [DOI] Compression of Dense and Regular Point Clouds
B. Merry, P. Marais, and J. Gain
in Proceedings of the 4th International Conference on Computer Graphics, Virtual Reality, Visualisation and Interaction in Africa, New York, NY, USA, 2006, p. 15–20.
[Bibtex]

@inproceedings{Merry2006B,
author = {Merry, Bruce and Marais, Patrick and Gain, James},
title = {Compression of Dense and Regular Point Clouds},
year = {2006},
isbn = {1595932887},
publisher = {Association for Computing Machinery},
address = {New York, NY, USA},
url = {https://doi.org/10.1145/1108590.1108593},
doi = {10.1145/1108590.1108593},
booktitle = {Proceedings of the 4th International Conference on Computer Graphics, Virtual Reality, Visualisation and Interaction in Africa},
pages = {15–20},
numpages = {6},
keywords = {compression, range scanning, spanning tree, point clouds},
location = {Cape Town, South Africa},
series = {AFRIGRAPH ’06}
}

[PDF] [DOI] Techniques for visualization of carbohydrate molecules
M. Kuttel, J. Gain, A. Burger, and I. Eborn
Journal of Molecular Graphics and Modelling, vol. 25, iss. 3, pp. 380-388, 2006.
[Bibtex]

@article{Kuttel2006,
title = "Techniques for visualization of carbohydrate molecules",
journal = "Journal of Molecular Graphics and Modelling",
volume = "25",
number = "3",
pages = "380 - 388",
year = "2006",
issn = "1093-3263",
doi = "https://doi.org/10.1016/j.jmgm.2006.02.007",
url = "http://www.sciencedirect.com/science/article/pii/S1093326306000453",
author = "Michelle Kuttel and James Gain and Anton Burger and Ian Eborn",
keywords = "Carbohydrate, Polysaccharide, Visualization, Silhouette, Transparency",
abstract = "Standard molecular visualizations, such as the classic ball-and-stick model, are not suitable for large, complex molecules because the overall molecular structure is obscured by the atomic detail. For proteins, the more abstract ribbon and cartoon representations are instead used to reveal large scale molecular conformation and connectivity. However, there is currently no accepted convention for simplifying oligo- and polysaccharide structures. We introduce two novel visualization algorithms for carbohydrates, incorporated into a visualization package, CarboHydra. Both algorithms highlight the sugar rings and backbone conformation of the carbohydrate chain, ignoring ring substituents. The first algorithm, termed PaperChain, emphasizes the type and conformation of the carbohydrate rings. The second, Twister, emphasizes the relative orientation of the rings. We further include two rendering enhancements to augment these visualizations: silhouettes edges and a translucent overlay of the ball-and-stick atomic representation. To demonstrate their utility, the algorithms and visualization enhancements are here applied to a variety of carbohydrate molecules. User evaluations indicate that they present a more useful view of carbohydrate structure than the standard ball-and-stick representation. The algorithms were found to be complementary, with PaperChain particularly effective for smaller carbohydrates and Twister useful at larger scales for highlighting the backbone twist of polysaccharides."
}

[PDF] [DOI] Affective Scene Generation
C. Hultquist, J. Gain, and D. Cairns
in Proceedings of the 4th International Conference on Computer Graphics, Virtual Reality, Visualisation and Interaction in Africa, New York, NY, USA, 2006, p. 59–63.
[Bibtex]

@inproceedings{Hultquist2006,
author = {Hultquist, Carl and Gain, James and Cairns, David},
title = {Affective Scene Generation},
year = {2006},
isbn = {1595932887},
publisher = {Association for Computing Machinery},
address = {New York, NY, USA},
url = {https://doi.org/10.1145/1108590.1108600},
doi = {10.1145/1108590.1108600},
booktitle = {Proceedings of the 4th International Conference on Computer Graphics, Virtual Reality, Visualisation and Interaction in Africa},
pages = {59–63},
numpages = {5},
keywords = {virtual environments, function approximation, procedural models, radial basis function networks},
location = {Cape Town, South Africa},
series = {AFRIGRAPH ’06}
}

[PDF] [VIDEO] [DOI] Warp sculpting
J. Gain and P. Marais
IEEE Transactions on Visualization and Computer Graphics, vol. 11, iss. 2, pp. 217-227, 2005.
[Bibtex]

@ARTICLE{Gain2005,
author={James {Gain} and Patrick {Marais}},
journal={IEEE Transactions on Visualization and Computer Graphics},
title={Warp sculpting},
year={2005},
volume={11},
number={2},
pages={217-227},
abstract={The task of computer-based free-form shape design is fraught with practical and conceptual difficulties. Incorporating elements of traditional clay sculpting has long been recognized as a means of shielding the user from these complexities. We present warp sculpting, a variant of spatial deformation, which allows deformations to be initiated by the rigid body transformation or uniform scaling of volumetric tools. This is reminiscent of a tool imprinting, flexing, and molding clay. Unlike previous approaches, the deformation is truly interactive. Tools, encoded in a distance field, can have arbitrarily complex shapes. Although individual tools have a static shape, several tools can be applied simultaneously. We enhance the basic formulation of warp sculpting in two ways. First, deformation is toggled to automatically overcome the problem of "sticky" tools, where the object's surface clings to parts of a tool that are moving away. Second, unlike many other spatial deformations, we ensure that warp sculpting remains foldover-free and, hence, prevent self-intersecting objects.},
keywords={mesh generation;virtual reality;solid modelling;warp sculpting;computer-based free-form shape design;clay sculpting;rigid body transformation;spatial deformation;self-intersection;remeshing;interactive modeling;Shape;Deformable models;Physics computing;Computational efficiency;Computational modeling;Finite element methods;Spatial resolution;Fasteners;Surface reconstruction;Usability;Index Terms- Interactive modeling;spatial deformation;self-intersection;remeshing.;Algorithms;Computer Graphics;Computer Simulation;Image Interpretation, Computer-Assisted;Imaging, Three-Dimensional;Information Storage and Retrieval;Numerical Analysis, Computer-Assisted;Pattern Recognition, Automated;Sculpture;User-Computer Interface},
doi={10.1109/TVCG.2005.36},
ISSN={1941-0506},
month={March},
}

[PDF] [DOI] Creation and Control of Real-time Continuous Level of Detail on Programmable Graphics Hardware
R. Southern and J. Gain
Computer Graphics Forum, vol. 22, iss. 1, pp. 35-48, 2003.
[Bibtex]

@article{Southern2003,
author = {Southern, Richard and Gain, James},
title = {Creation and Control of Real-time Continuous Level of Detail on Programmable Graphics Hardware},
journal = {Computer Graphics Forum},
volume = {22},
number = {1},
pages = {35-48},
doi = {10.1111/1467-8659.t01-1-00644},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/1467-8659.t01-1-00644},
eprint = {https://onlinelibrary.wiley.com/doi/pdf/10.1111/1467-8659.t01-1-00644},
abstract = {Abstract Continuity in level of detail sequences is essential in hiding visual artefacts that occur when switching between discrete levels of detail. However, construction and implementation of these sequences is prohibitively complex. We present a new structure, the g-mesh, which greatly simplifies the implementation of continuous level of detail in large scenes. We also introduce a novel greedy predictive level of detail control system suited to the g-mesh. Finally we achieve a dramatic improvement in the rendering of morphing sequences by exploiting current graphics hardware. ACM CSS: I.3.5 Computational Geometry and Object Modeling—Geometric Transformations, Object Hierarchies, I.3.6 Methodology and Techniques—Graphics Data Structures},
year = {2003}
}

[PDF] [DOI] Topology Alteration for Virtual Sculpting Using Spatial Deformation
B. Steyn and J. Gain
in Proceedings of the 2nd International Conference on Computer Graphics, Virtual Reality, Visualisation and Interaction in Africa, New York, NY, USA, 2003, p. 63–68.
[Bibtex]

@inproceedings{Steyn2003,
author = {Steyn, Barry and Gain, James},
title = {Topology Alteration for Virtual Sculpting Using Spatial Deformation},
year = {2003},
isbn = {1581136439},
publisher = {Association for Computing Machinery},
address = {New York, NY, USA},
url = {https://doi.org/10.1145/602330.602343},
doi = {10.1145/602330.602343},
booktitle = {Proceedings of the 2nd International Conference on Computer Graphics, Virtual Reality, Visualisation and Interaction in Africa},
pages = {63–68},
numpages = {6},
keywords = {computer graphics, computer modelling, topology alteration, virtual sculpting},
location = {Cape Town, South Africa},
series = {AFRIGRAPH ’03}
}

[PDF] [DOI] Accelerating Ray Shooting through Aggressive 5D Visibility Preprocessing
A. Sharpe, M. Hampton, S. Nirenstein, J. Gain, and E. Blake
in Proceedings of the 2nd International Conference on Computer Graphics, Virtual Reality, Visualisation and Interaction in Africa, New York, NY, USA, 2003, p. 95–100.
[Bibtex]

@inproceedings{Sharpe2003,
author = {Sharpe, Adrian and Hampton, Matthew and Nirenstein, Shaun and Gain, James and Blake, Edwin},
title = {Accelerating Ray Shooting through Aggressive 5D Visibility Preprocessing},
year = {2003},
isbn = {1581136439},
publisher = {Association for Computing Machinery},
address = {New York, NY, USA},
url = {https://doi.org/10.1145/602330.602348},
doi = {10.1145/602330.602348},
booktitle = {Proceedings of the 2nd International Conference on Computer Graphics, Virtual Reality, Visualisation and Interaction in Africa},
pages = {95–100},
numpages = {6},
keywords = {global illumination, ray casting, ray shooting, visibility, ray tracing},
location = {Cape Town, South Africa},
series = {AFRIGRAPH ’03}
}

[PDF] [DOI] Exact From-Region Visibility Culling
S. Nirenstein, E. Blake, and J. Gain
in Proceedings of the 13th Eurographics Workshop on Rendering, Goslar, DEU, 2002, p. 191–202.
[Bibtex]

@inproceedings{Nirenstein2002,
author = {Nirenstein, S. and Blake, E. and Gain, J.},
title = {Exact From-Region Visibility Culling},
year = {2002},
isbn = {1581135343},
publisher = {Eurographics Association},
address = {Goslar, DEU},
doi={10.2312/EGWR/EGWR02/191-202},
booktitle = {Proceedings of the 13th Eurographics Workshop on Rendering},
pages = {191–202},
numpages = {12},
location = {Pisa, Italy},
series = {EGRW ’02}
}

[PDF] [DOI] Preventing self-intersection under free-form deformation
J. E. Gain and N. A. Dodgson
IEEE Transactions on Visualization and Computer Graphics, vol. 7, iss. 4, pp. 289-298, 2001.
[Bibtex]

@ARTICLE{Gain2001,
author={J. E. {Gain} and N. A. {Dodgson}},
journal={IEEE Transactions on Visualization and Computer Graphics},
title={Preventing self-intersection under free-form deformation},
year={2001},
volume={7},
number={4},
pages={289-298},
abstract={Free-Form Deformation (FFD) is a versatile and efficient modeling technique which transforms an object by warping the surrounding space. The conventional user-interface is a lattice of movable control points but this tends to be cumbersome and counterintuitive. Directly Manipulated Free-Form Deformation (DMFFD) allows the user to drag object points directly and has proven useful in an interactive sculpting context. A serious shortcoming of both FFD and DMFFD is that some deformations cause self-intersection of the object. This is unrealistic and compromises the object's validity and suitability for later use. An in-built self-intersection test is thus required for FFD and its extensions to be truly robust In this paper, we present the following novel results set of theoretical conditions for preventing self-intersection by ensuring the injectivity (one-to-one mapping) of FFD, an exact. (necessary and sufficient) injectivity test which is accurate but computationally costly, an efficient but approximate injectivity test which is a sufficient condition only, and a new form of DMFFD which acts by composing many small injective deformations. The latter expands the range of possible deformations without sacrificing the speed of the approximate test.},
keywords={computer graphics;Free-Form Deformation;Directly Manipulated Free-Form Deformation;DMFFD;FFD;direct manipulation;drag object points;self-intersection;space homeomorphism;interactive sculpting;Lattices;Automatic testing;Deformable models;Robustness;Shape control;Solids;Sufficient conditions;Animation;Embedded computing;Topology},
doi={10.1109/2945.965344},
ISSN={1941-0506},
month={Oct},}

[PDF] Adaptive Refinement and Decimation under Free-Form Deformation
J. Gain and N. Dodgson
in Eurographics UK ’99, 1999.
[Bibtex]

@inproceedings{Gain1999,
author = {Gain, James and Dodgson, Neil},
title = {Adaptive Refinement and Decimation under Free-Form Deformation},
booktitle = {Eurographics UK '99},
location = {Cambridge (UK)},
year = {1999},
}

[PDF] [DOI] Building the second generation of parallel/distributed virtual reality systems
S. Bangay, J. Gain, G. Watkins, and K. Watkins
Parallel Computing, vol. 23, iss. 7, pp. 991-1000, 1997.
[Bibtex]

@article{Bangay1997,
title = "Building the second generation of parallel/distributed virtual reality systems",
journal = "Parallel Computing",
volume = "23",
number = "7",
pages = "991 - 1000",
year = "1997",
note = "Parallel graphics and visualisation",
issn = "0167-8191",
doi = "https://doi.org/10.1016/S0167-8191(97)00040-9",
url = "http://www.sciencedirect.com/science/article/pii/S0167819197000409",
author = "Shaun Bangay and James Gain and Greg Watkins and Kevan Watkins",
keywords = "Distributed virtual reality, Ant Psychology",
abstract = "We present the RhoVeR (Rhodes Virtual Reality) system and classify it as a second generation parallel/distributed virtual reality (DVR) system. We discuss the components of the system and thereby demonstrate its support for virtual reality application development, its configurable, parallel and distributed nature, and its synthesis of first generation DVR techniques."
}

[PDF] Enhancing Spatial Deformation for Virtual Sculpting
J. Gain
PhD Thesis, University of Cambridge, 2000.
[Bibtex]

@phdthesis{thesisgain2000a,
author = {Gain, James},
year = {2000},
institution = {University of Cambridge},
month = {09},
pages = {161},
title = {Enhancing Spatial Deformation for Virtual Sculpting}
}

[PDF] Virtual Sculpting: An Investigation of Directly Manipulated Free-Form Deformation in a Virtual Environment
J. Gain
Master Thesis, Rhodes University, 1996.
[Bibtex]

@mastersthesis{thesisgain1998a,
author = {Gain, James},
year = {1996},
month = {04},
institution = {Rhodes University},
pages = {},
title = {Virtual Sculpting: An Investigation of Directly Manipulated Free-Form Deformation in a Virtual Environment}
}