  We proposed Precomputed RadianceTransfer of GaussianSplats (PRTGS), a
real-time high-quality relighting method for Gaussian splats in low-frequency
lighting environments that captures soft shadows and interreflections by
precomputing 3D Gaussian splats' radiance transfer. Existing studies have
demonstrated that 3D Gaussian splatting (3DGS) outperforms neural fields'
efficiency for dynamic lighting scenarios. However, the current relighting
method based on 3DGS still struggles to compute high-quality shadow and
indirect illumination in real time for dynamic light, leading to unrealistic
rendering results. We solve this problem by precomputing the expensive
transport simulations required for complex transfer functions like shadowing,
the resulting transfer functions are represented as dense sets of vectors or
matrices for every Gaussian splat. We introduce distinct precomputing methods
tailored for training and rendering stages, along with unique ray tracing and
indirect lighting precomputation techniques for 3D Gaussian splats to
accelerate training speed and compute accurate indirect lighting related to
environment light. Experimental analyses demonstrate that our approach achieves
state-of-the-art visual quality while maintaining competitive training times
and allows high-quality real-time (30+ fps) relighting for dynamic light and
relatively complex scenes at 1080p resolution.
