Standard 3DGS conflates appearance and geometry, hurting both. Adding a geometry-specific opacity parameter lets you get better rendering quality AND more accurate 3D surfaces, especially for complex scenes with transparent objects.
This paper identifies a fundamental limitation in 3D Gaussian Splatting (3DGS)—it struggles to represent both realistic appearance and accurate geometry simultaneously. The authors propose a simple fix: adding a separate opacity parameter for geometry to each Gaussian splat, which decouples how the model handles texture rendering versus surface reconstruction.