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 an IMPRS fellowship from the Max-Planck Institute. I stayed in Saarbrücken to pursue a PhD degree, initially supported by the IMPRS and later as a researcher at the Intel Visual Computing Instute. I then did a research internship at Disney Research Zürich and an R&D internship at Weta Digital. I have also worked briefly as a consultant at Chaos Group, the creators of the V-Ray renderer. I currently work for Solid Angle (now member of the Autodesk family) – the team behind the award-winning Arnold renderer.

5 Jan 2017
Published a revision 2 of the joint path sampling paper with a fixed typo in equation.
5 Aug 2016
The abstract and slides of our SIGGRAPH 2016 blue-noise dithered sampling talk are now online.
8 Jun 2016
Our projective blue-noise sampling paper will be presented at EGSR 2016.
9 May 2015
I was awarded the PhD Thesis Award at Eurographics 2016.

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.