Differentiable rendering is a technique that aims to invert the rendering process to enable optimizing rendering parameters from a set of images. In this article, we present a differentiable volume rendering solution called DiffTetVR for tetrahedral meshes. Unlike previous works based on regular grids, this enables the optimization of vertex positions and the local subdivision of the mesh without relying on multigrid methods. We present an efficient implementation of the forward rendering process, deduce the derivatives for the backwards pass and regularization terms for avoiding degenerate tetrahedra, and finally show how the tetrahedral mesh can be subdivided locally to enable a coarse-to-fine optimization process. The source code is made publicly available on GitHub at https://github.com/chrismile/DiffTetVR.

翻译：可微分渲染是一种旨在逆转渲染过程的技术，使得能够从一组图像中优化渲染参数。本文提出了一种针对四面体网格的可微分体积渲染解决方案，称为DiffTetVR。与以往基于规则网格的研究不同，该方法能够优化顶点位置并实现网格的局部细分，而无需依赖多重网格方法。我们提出了一种高效的前向渲染过程实现，推导了反向传播的导数以及避免退化四面体的正则化项，最后展示了如何对四面体网格进行局部细分以实现从粗到细的优化过程。源代码已在GitHub上公开，地址为https://github.com/chrismile/DiffTetVR。