Differentiable Shadow Fields: Ray-Calibrated Visibility for Inverse Rendering

Visibility is fundamental to rendering and inverse rendering (IR), where occlusion must be repeatedly evaluated as lighting, geometry, or scene parameters change. Ray tracing provides accurate visibility, but requires repeated geometric intersection tests and can become costly under large numbers of queries. Precomputed methods such as shadow maps are efficient, but light-dependent, update-sensitive, and not naturally differentiable with respect to light positions. We introduce Differentiable Shadow Fields (DSF), a ray-calibrated, light-independent visibility representation for IR. DSF amortizes scene geometry into a shared scalar field and evaluates visibility along finite segments between surface points and arbitrary light endpoints. Starting from an unsigned distance field, we calibrate the representation and its differentiable query function using ray-traced visibility supervision. This allows DSF to approximate ray-traced visibility while avoiding source-mesh intersection tests at inference time. Once constructed, DSF supports arbitrary light queries without rebuilding and remains differentiable with respect to light positions. Experiments show visibility and shadow accuracy close to ray tracing with substantially lower query cost, and demonstrate its use in shadow-driven light localization, inverse-rendering pipelines, and compositional scene editing