Alexander Rath, M.Sc.


Alexander Rath, M.Sc. Researcher

German Research Center for Artificial Intelligence (DFKI)
Agents and Simulated Reality
Saarland Informatics Campus D3 4, 66123 Saarbrücken, Germany
Saarland University
Computer Graphics Lab
Saarland Informatics Campus E1 1, Room E16, 66123 Saarbrücken, Germany
Research Interests
importance sampling wave optics lens design


Hi, I’m Alex. I grew up in a small village in Rheinland-Pfalz with more cows than residents, but it still had better internet than where I live in Saarland now ;-) I’m trying to pick up a bit of French here and there, but I mostly only speak English and German.

What got me obsessed with computer graphics is that you can get photorealistic images with just a single elegant equation! And now I am researching how you can do that as efficiently as possible with good importance sampling, algorithmic improvements or just clever implementations. Apart from my light transport research, I’m also in charge of the radar research at the chair. There’s a lot of interesting analogies between light and radar, which means you can transfer cool ideas from one research field to the other. But there’s also plenty of challenging differences, in particular wave effects. I also do some research in machine learning and lens design on the side, and I occasionally like to explore unusual ideas like shadow transport simulation or block-chain ray-tracing.

When I’m not staring at my monitor wall at the chair, I can usually be found touring with my band, doing event photography, building antennas or playing pen and paper. Oh, and I have this bad habbit of drumming on tables, which sometimes gets me into trouble…


A. Rath Ö. Yazici P. Slusallek
Focal Path Guiding for Light Transport Simulation
Publication Type: Article, SIGGRAPH '23 Conference Proceedings
  author = {Rath, Alexander and Yazici, \"{O}mercan and Slusallek, Philipp},
  title = {Focal Path Guiding for Light Transport Simulation},
  year = {2023},
  isbn = {9798400701597},
  publisher = {Association for Computing Machinery},
  address = {New York, NY, USA},
  url = {},
  doi = {10.1145/3588432.3591543},
  articleno = {30},
  numpages = {10},
A. Rath P. Grittmann S. Herholz P. Weier P. Slusallek
EARS: Efficiency-Aware Russian Roulette and Splitting
Publication Type: Article, ACM Transactions on Graphics (Proceedings of SIGGRAPH 2022), 41(4): 81:1-81:14, 2022
  author          = {Rath, Alexander and Grittmann, Pascal and Herholz, Sebastian and Weier, Philippe and Slusallek, Philipp},
  title           = {EARS: Efficiency-Aware Russian Roulette and Splitting},
  journal         = {ACM Transactions on Graphics (Proceedings of SIGGRAPH 2022)},
  numpages        = {14},
  volume          = {41},
  number          = {4},
  articleno       = {81},
  year            = {2022},
  month           = {jul},
  doi             = {10.1145/3528223.3530168},
  publisher       = {ACM}
A. Rath P. Grittmann Sebastian Herholz Petr Vévoda P. Slusallek J. Křivánek
Variance-Aware Path Guiding
Publication Type: Article, ACM Transactions on Graphics (Proceedings of SIGGRAPH 2020), 39(4): 151:1-151:12, 2020
  author          = {Rath, Alexander and Grittmann, Pascal and Herholz, Sebastian and V{\'{e}}voda, Petr and Slusallek, Philipp and K{\v{r}}iv{\'{a}}nek, Jaroslav},
  title           = {Variance-Aware Path Guiding},
  journal         = {ACM Transactions on Graphics (Proceedings of SIGGRAPH 2020)},
  pages           = {151:1--151:12},
  volume          = {39},
  number          = {4},
  year            = 2020,
  month           = jul,
  date            = {2020-07-17/2020-07-20},
  doi             = {10.1145/3386569.3392441},
  publisher       = {ACM}