Skip to Main content Skip to Navigation
Journal articles

Reparameterizing Discontinuous Integrands for Differentiable Rendering

Guillaume Loubet 1 Nicolas Holzschuch 2 Wenzel Jakob 1
2 MAVERICK - Models and Algorithms for Visualization and Rendering
Inria Grenoble - Rhône-Alpes, LJK - Laboratoire Jean Kuntzmann, INPG - Institut National Polytechnique de Grenoble
Abstract : Differentiable rendering has recently opened the door to a number of challenging inverse problems involving photorealistic images, such as computational material design and scattering-aware reconstruction of geometry and materials from photographs. Differentiable rendering algorithms strive to estimate partial derivatives of pixels in a rendered image with respect to scene parameters, which is difficult because visibility changes are inherently non-differentiable. We propose a new technique for differentiating path-traced images with respect to scene parameters that affect visibility, including the position of cameras, light sources, and vertices in triangle meshes. Our algorithm computes the gradients of illumination integrals by applying changes of variables that remove or strongly reduce the dependence of the position of discontinuities on differentiable scene parameters. The underlying parameterization is created on the fly for each integral and enables accurate gradient estimates using standard Monte Carlo sampling in conjunction with automatic differentiation. Importantly, our approach does not rely on sampling silhouette edges, which has been a bottleneck in previous work and tends to produce high-variance gradients when important edges are found with insufficient probability in scenes with complex visibility and high-resolution geometry. We show that our method only requires a few samples to produce gradients with low bias and variance for challenging cases such as glossy reflections and shadows. Finally, we use our differentiable path tracer to reconstruct the 3D geometry and materials of several real-world objects from a set of reference photographs.
Complete list of metadatas

Cited literature [50 references]  Display  Hide  Download

https://hal.inria.fr/hal-02497191
Contributor : Nicolas Holzschuch <>
Submitted on : Tuesday, March 3, 2020 - 3:00:36 PM
Last modification on : Thursday, March 26, 2020 - 8:49:43 PM

File

differentiable-pt-cov.pdf
Files produced by the author(s)

Identifiers

Collections

Citation

Guillaume Loubet, Nicolas Holzschuch, Wenzel Jakob. Reparameterizing Discontinuous Integrands for Differentiable Rendering. ACM Transactions on Graphics, Association for Computing Machinery, 2019, 38 (6), pp.228:1 - 228:14. ⟨10.1145/3355089.3356510⟩. ⟨hal-02497191⟩

Share

Metrics

Record views

93

Files downloads

292