Faster and higher quality global illumination

Lead Research Organisation: Swansea University
Department Name: College of Science


Global illumination brings realistic and detailed lighting environments to Computer Graphics imagery at the expense of very high computational cost. Although most people are unaware, they experience its imagery when they have renderings of a new kitchen design, in public displays of new architecture, and in a variety of film, advertising and entertainment. The computer imagery produced by this technique can deliver the highest form of realism achievable by Computer Graphics as it models indirect light (reflected from other surfaces) and not just light direct from light sources in the scene.Such realism is now a standard requirement for the above applications and it is also gaining popularity in the virtual reality and scientific visualization communities as the advantages of increased perception and understanding are now recognised and outweigh the disadvantages of production time.Current approaches for fast global illumination place limits on the scene geometry, depth of light paths, numbers of samples, or the materials in the scene. Within these limitations it is possible to employ large caches for computation reuse (only in static scenes), or create simplified algorithms on the GPU, but always at the cost of reducing rendering accuracy.The aim of this research is to work towards real-time and accurate global illumination techniques by exploring new approaches to biased rendering methods. We will apply hierarchical techniques, clustering, ray and photon statistics and information, edge detection and combine other appropriate techniques to reduce the complexity and computation of global illumination whilst maintaining or enhancing visual accuracy.These improved timings and render quality will be demonstrated within a software package. The improved algorithms will allow the above application areas to produce higher quality images at reduced cost.

Planned Impact

The overall aim of this research is to work towards real-time and accurate global illumination methods. In the short term, the methods created during this research will have direct impact within the animation and design software industry. Such software is used within the architecture, design, engineering and entertainment industries, hence this research will have indirect impact within those industries (typically allowing more realistic rendering with fewer resources). The global market leader for those segments is Autodesk through its 3D Studio Max and AutoCad (and derivative) products. Within that product there are plug-ins for global illumination provided by Mental Images (now owned by NVidia) namely Mental Ray and Chaos Graphics namely V-Ray. Those plug-ins are the primary target for this research. From a UK perspective, we have game producers (e.g. Bizarre Creations, Liverpool), render farms (e.g. Render Nation, Liverpool) and resellers (e.g. bluegfx, London). I applied for a patent through Swansea University for previous work. During the process a market assessment was carried out by Nicholas Jones and Associates. Contacts were made with all of the above companies (the unedited preliminary report is attached to this proposal). Dissemination and commercial exploitation of this research will take place through that route. In the medium term (5-10 years), I anticipate that hardware advances coupled with research of software methods (as proposed here) will lead to real-time global illumination. This will have a direct impact on the games industry where photo-realistic rendering is considered a competitive advantage. Impact will filter through to consumers of the above industries in the form of more realistic games, better special effects in films, and more accurate portrayals of development plans, products, cultural artefacts and immersive virtual environments. The games industry is important to the UK: According to the Entertainment and Leisure Software Publishers Association the industry was worth over 7.3 billion to the UK in the last 2 years [cited in the main proposal]. Therefore, there is good potential for impact to the wealth of the UK, which can be through the following routes: : Exploitation of IP, therefore bringing licensing income into the UK : Collaboration with the main industrial players, therefore bringing research funding and investment into the UK : Creating software to compete with the large players, with an edge over the existing players in terms of computational demand or realism. The third option would require a great deal of investment in order to create a competitor to existing products due to the scale of their operations. The first two options are realistic, and the attached market assessment demonstrates the contacts are in place and the positive comments this research has received.


10 25 50

publication icon
Spencer B (2013) Photon Parameterisation for Robust Relaxation Constraints. in Computer graphics forum : journal of the European Association for Computer Graphics

publication icon
Spencer B (2013) 2013 Cover Image: Prism in Computer Graphics Forum

publication icon
Spencer B (2013) Progressive photon relaxation in ACM Transactions on Graphics

Description The primary discovery has been the realisation that relaxed photon maps can produce low bias and low variance images for Computer Graphics Imagery. Our methods produce considerably better images than previous methods. Due to lower numbers of photons required in the density estimate, the method is also faster to render.
Exploitation Route First, the method could be integrated into rendering software and used to improve the run-time and image quality of those software and applications.
Secondly, the method demonstrates that statistical operations (kernel density estimation), could be improved by following the techniques we have taken.
Sectors Creative Economy,Digital/Communication/Information Technologies (including Software)

Description ACM SIGGRAPH 2012 Tutorial 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact Together with the RA Ben Spencer we have been carrying out research in the area of photon mapping. In recognition of the upcoming publications in this area as a direct result of this grant funding, we were invited to participate in a tutorial at SIGGRAPH 2012. Ben presented our work on photon relaxation as part of the tutorial as documented

The audience contained academic and industrial attendees.

Recognition of Swansea as a leading centre for Photon Mapping research.
Year(s) Of Engagement Activity 2012