Илиян is how my name is written in Cyrillic, the alphabet used in my mother tongue, Bulgarian. I can say I am a happy man, as I love the two most essential ingredients of my life – my darling and my job. I like technology and gadgets, I'm fascinated by science. I appreciate clever design, beautiful pictures, and healthy good food. I like playing tennis, skiing, driving cars, and I'm always in search for interesting travel destinations around the globe.


I do computer graphics – producing photo-realistic images of virtual 3D environments. I investigate methods for efficient physically based light transport simulation, with the ultimate goal of rendering synthetic pictures that are indistinguishable from real photographs. This involves solving various problems arising from the physical nature of light, the mathematical models used to describe light transport, and the practical implementation of the simulation on a computer. Check out my publications.


Computer graphics is a fascinating synergy of science, technology and art, which comes in many different flavors. Solving complex mathematical equations and writing intricate computer programs can be very rewarding when the final result is a beautiful picture or a movie that can be also appreciated by non-technicians. Realistic image synthesis has applications in animated and feature films, commercials, architectural visualization, industrial design, games, and other areas.


I obtained a bachelor degree in computer science from Sofia University, Bulgaria, and a master degree from Saarland University, Germany, with a fellowship from the Max-Planck Institute. I stayed in Saarbrücken as a PhD student and researcher at the Intel Visual Computing Instute. I did internships at Disney Research Zürich and Weta Digital, and a consultancy at Chaos Group (the V-Ray renderer). I then joined the Arnold renderer team, initially at Solid Angle and then Autodesk. I am currently a research scientist at Adobe.

1 Jul 2022
Our EGSR 2022 paper on stratified importance resampling is now available online.
5 May 2022
Posted three SIGGRAPH 2022 technical papers.
3 May 2021
Our SIGGRAPH 2021 technical paper on unbiased differential light transport estimation is now available online.
1 Mar 2021
Our EUROGRAPHICS 2021 paper on correlation-aware multiple importance sampling is now available online.

In the real world, light particles called photons are emitted from light sources, travel through space, and interact with the objects in the environment until absorption. Some of them eventually reach the camera sensors (or our eyes), which in turn record the light energy and convert it to an image. This process can be simulated on a computer to produce a realistic image of a virtual (i.e. non-existing) environment with physically correct lighting.

The physical laws that govern light transport and the mathematical models that formalize the image rendering problem are generally well understood. However, carrying out an accurate light transport simulation on a computer can be a challenging task in practice – billions of light particles need to be tracked, each particle can interact with arbitrarily many objects, and typically only a small fraction of all emitted particles eventually make their way to the camera.

The main focus of my work can be very obscurely shortly summarized as investigating methods for the efficient discovery of light transport paths that contribute energy to the camera. Such methods can tremendously increase rendering efficiency, as they aim to concentrate the computational effort where it pays off most. Higher efficiency allows for handling larger environments, simulating more complex lighting, and producing more visually stunning images.