Traditional rendering implies computation of realistic images given a standard 3D scene description. Scene description is a quadruple: geometry, light sources, materials, virtual camera. Though the problem with such formulation is being attacked by graphics community for quite a long time, the performance of currently developed algorithms is still too low for many practical applications. We contribute to overall progress in this area by suggesting new algorithms, based on novel numerical methods, as well as better suited for modern hardware.

Photo realistic images synthesis is one of the central problems of traditional rendering. One of the ways to achieve realism is to apply physically based algorithms, which implies modeling of light interaction with scene objects, basing on the laws of physics. If the modeled light behavior corresponds to it's behavior in the real life, the received images are guaranteed to look realistic. However, such modeling can be computationally expensive. The rise of computing power solves this problem only partially because complexity of the processed virtual scenes increases as well. Thus, there is a vital need to improve the performance of all related algorithms. So far our main efforts in this area were concentrated on the following issues: improvement of ray tracing speed [1], extending traditionally used Phong material model to handle fuzzy reflections [2], use of quasi-Monte Carlo algorithm in the general setting to increase the convergence of Global Illumination algorithms [3], visualization of rays in (quasi-)Monte Carlo algorithms for debugging, promotional and educational purposes [4].Here are some images, which demonstrate our results:

[1] Dmitriev K. Efficiency issues on ray tracing machine. // Graphicon '2000 conference proceedings, Moscow, Russia, August 25 - September 1, 2000, pp. 99-103.

[2] Kulikova A. and Dmitriev K. Fuzzy reflections rendering. Fuzzy reflections rendering. // Graphicon '2001 conference proceedings, N.Novgorod, Russia, August 25 - September 1, 2001, pp. 88-9.

[3] Dmitriev K. From Monte Carlo to quasi-Monte Carlo. // Graphicon '2002 conference proceedings, N.Novgorod, Russia, September 21-26, 2000.

[4] Kopylov E. and Dmitriev K. Light propagation visualization as a tool for 3d scene analysis in lighting design. // Computers & Graphics, Elsevier Science, vol. 24, num. 1, 2000, pp.31-39.

Traditionally OpenGL or DirectX APIs are used for rendering in interactive applications. Those APIs are fairly limited in the number of directly supported effects, which significantly reduces the images realism. We have developed a number of algorithms, which improve the realism by modeling lacking effects via modern hardware accelerators. This includes:

• shadows from multiple light sources;

• reflections;

• general surface BSDFs (Bi-directional Scattering Distribution Functions);

• lights with general intensity distributions;

Those effects are demonstrated by the below images, received exclusively using graphics hardware:

Currently only the use of graphics hardware allows to achieve interactive speed of rendering. Received images, however, often lack the physical accuracy required for many applications. One of the reasons is that hardware computes only direct lighting, leaving important indirect lighting effects without attention. We have developed a general Monte-Carlo framework, which is able to work both standalone, and in cooperation with graphics hardware. This framework is specifically designed for interactive applications and allows to update the global illumination rather then recompute it from the scratch after scene changes. This project is was performed in cooperation with Max-Planck Institute for Computer Science (http://www.mpi-sb.mpg.de/) and current results are published in [5].

[5]  Dmitriev K., Brabec S., Myszkowski K., and Seidel H.-P. Interactive global illumination using selective photon tracing. In Debevec P. and Gibson S., editors, // Rendering Techniques '2002 (Springer), Pisa, Italy, June 26-28, 2002, pp. 100-113.