Research Interests: James Gain

Dr. Gain is looking for Masters and Doctoral students in the following areas but is willing to consider students with their own topics in Computer Graphics and Virtual Reality:

Molecular Compression

Molecular simulations typically produce massive data-sets, on the order of terabytes of data. Storing and transmitting this data is thus a major bottleneck in the molecular analysis process. One way to overcome this is to compress the simulation data and this can be done most effectively with due consideration of its structure. Molecular chains can be treated as three-dimensional graphs and compressed accordingly. This project will extend work on compression of water molecules to other structures.

Distributed Simulation for Visual Effects

Simulation of natural phenomena such as water, fire and object collision and fracture is widespread in the Visual Effects industry. However, such simulation tends to be extremely compute intensive especially as the number of simulated particles is increased in order to ensure realism. Visual effects studios are often under intense time pressure and these simulations would thus benefit from execution on a cluster of computers. Fortunately, such clusters are already in use as “render farms”. This project seeks to parallelise simulations in order to create an effective “simulation farm”.

Procedural Methods

Procedural methods are an effective way of generating complex and realistic geometric scenes with little user input. They constitute a set of algorithmic techniques (fractals, L-systems, shape grammars and noise functions) that iteratively build structures like trees, terrain, road networks and buildings and are widely used for Games, Visual Effects and Virtual Environments. Unfortunately, the very fact that they require little user input works against these methods since they also afford little user control. One promising route for future research is to incorporate better control through sketch-based and example-driven interfaces. Another avenue is to apply procedural methods in new areas, such as mechanical assemblies.

Heritage Data

The Geomatics department at UCT is involved in an initiative to create an integrated database of architectural cultural heritage sites in Africa. The condition of these sites is deteriorating and given their importance in understanding and interpreting humankind's history, a permanent digital record is essential.

It is common practice in Geomatics to digitally capture the shape of buildings for analysis purposes, using laser range scanning. This produces a cloud of points that represent the position and colouration of samples on the building surface.

There are a number of projects arising from this rich data-set:

1. Automatic Hole-Filling - Unfortunately, due to constraints on the position of the laser scanner and the convolutions of the building point clouds often have gaps. An automated approach to filling these holes is to transplant complete surfaces from elsewhere in the model, using the edges around the hole as context.
2. Certainty Visualisation - Archaeologists are particularly concerned with any error that might arise during the capture process. Given the diversity of possible data sources (with scans from different devices at different times), it is worth portraying these uncertainties visually. The challenge here is to avoid overly distorting the normal rendering of the building and its textures.
3. Texture Matching - Scanning often produces two sets of data: digital photographs (texture) and laser scans (point clouds). For a truly effective representation of geometry and texture these data sets need to be registered but this can be challenging, particularly if the exact position and orientation of the scanning device is not known.
4. Display in Virtual Environments - In a digital museum setting it is worth attempting to convey something of the experience of seeing the original heritage site. Many of these sites, such as churches and fortresses, have a significant vertical component, which virtual environments traditionally represent poorly.