The Realistic Graphics Lab, or RGL for short, is a research group in the School of Computer and Communication Sciences at EPFL in Lausanne, Switzerland.

We develop rendering algorithms that simulate light to create realistic images of virtual worlds along with inverse rendering algorithms that go the opposite way and reconstruct 3D worlds from images. We disseminate our work through open source projects like the Mitsuba Renderer.


Differentiable Rendering

If we could back­propag­ate de­riv­at­ives through a ren­der­ing al­gorithm, then it should be pos­sible to em­ploy some vari­ant of gradi­ent des­cent to run a ren­der­ing al­gorithm “in re­verse” and re­con­struct the world from im­ages. This turns out to be sur­pris­ingly hard: ren­der­ing al­gorithms are very big pro­grams, which makes naïve back­propaga­tion slow and costly. We de­vel­op al­gorithms that ex­ploit phys­ic­al laws to be faster.

Physical realism

We build math­em­at­ic­al mod­els and al­gorithms that cap­ture the visu­al rich­ness of the world. This in­volves ana­lyz­ing samples in RGL's state-of-the-art meas­ure­ment labor­at­ory and sim­u­lat­ing sur­face mi­cro­struc­ture along with the spec­trum and po­lar­iz­a­tion of light.


We de­vel­op com­pilers that can trans­form de­scrip­tions of ren­der­ing and dif­fer­en­ti­able ren­der­ing tasks in­to ef­fi­cient com­pu­ta­tion­al ker­nels for CPUs or GPUs with ray tra­cing hard­ware ac­cel­er­a­tion. Ob­tain­ing high per­form­ance re­quires ker­nel fu­sion, dif­fer­en­ti­ation, and spe­cial­ized op­tim­iz­a­tion passes.


28 July 2023

Rami Tab­bara joins RGL as a re­search en­gin­eer. He will par­ti­cip­ate in the de­vel­op­ment of the lab's next-gen­er­a­tion dif­fer­en­ti­able ren­der­ing soft­ware in­fra­struc­ture. Wel­come, Rami!

25 November 2022

De­lio Vi­cini suc­cess­fully de­fen­ded his Ph.D. thes­is. Con­grats, Dr. Vi­cini!