Sebastien Speierer
Staff Research Engineer at Meta
Lausanne, Vaud, Switzerland
Summary
🤩
Rockstar🎓
Top SchoolSebastien Speierer is a Staff Research Engineer with 11 years focused on rendering, performance engineering, and differential rendering, now based in Lausanne and currently at Meta. He has deep open-source impact on the Mitsuba renderer family and the Enoki vectorization library, contributing test automation, CUDA/autodiff improvements, Windows build support, and critical memory and OptiX fixes. His background spans industry leaders (Weta, Pixar) and academia (EPFL), where he combined production-quality engineering with research on spatially-varying reflectance, volume rendering, and many-lights sampling. Known for pragmatic problem solving, he often tackles low-level performance and stability issues—writing tests and removing unnecessary scheduling to eliminate memory leaks. He brings a rare blend of mathematical rigor and practical systems work, demonstrated by test suites and automated validations for complex BSDF and warping functions. Colleagues rely on him to “just keep rendering” while making engines faster, more reliable, and easier to integrate.
11 years of coding experience
9 years of employment as a software developer
Master's degree, Computer Science, Master's degree, Computer Science at EPFLExchange, Computer Science, Exchange, Computer Science at Carnegie Mellon University
English, French
Github Skills (20)
unit-testing10
autodiff10
c-language10
python10
memory-management10
raytracing10
performance-optimization10
cuda10
cprogramming-language10
linear-algebra10
test-automation10
numerical9
computation9
matrix9
mat9
Programming languages (6)
Github contributions (5)
mitsuba-renderer/mitsuba3
Jul 2020 - Dec 2022
Mitsuba 3: A Retargetable Forward and Inverse Renderer
Role in this project:
Back-end Developer & Performance Engineer
Back-end Developer & Performance EngineerContributions:79 reviews, 1119 commits, 85 PRs in 2 years 5 months
Contributions summary:Sebastien primarily focused on optimizing and refining the Mitsuba 3 rendering engine. Their contributions involved fixing memory allocation issues within the sampler, addressing and correcting problems related to OptiX ray testing, and removing unnecessary scheduling to fix memory leaks. These changes demonstrate a deep understanding of the rendering pipeline and efforts to improve performance. Furthermore, the user made architectural improvements related to the scene management and integration with Enoki next.
mitsubarendererinverseforward
mitsuba-renderer/mitsuba2
Feb 2017 - Jul 2021
Mitsuba 2: A Retargetable Forward and Inverse Renderer
Role in this project:Test Automation & Rendering Engineer
Test Automation & Rendering EngineerContributions:5 releases, 38 reviews, 516 commits in 4 years 6 months
Contributions summary:Sebastien contributed significantly to the testing and quality assurance of the Mitsuba 2 rendering framework. Their work focused on implementing a test suite for various warping and BSDF functions, ensuring their accuracy and reliability. The user developed a comprehensive set of tests for key functions and plugins, demonstrating a strong understanding of testing methodologies and the underlying mathematical concepts. They also established automated tests, and contributed to ensuring backward compatibility with existing rendering techniques.
forwardrendering-enginerendererrenderingmitsuba
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