A Logistic Model for the Degradation of Triangle Mesh Normals

The performance of shading and ray-tracing algorithms depends heavily on the quality of the surface normal information. As a result, in many visual applications normal information turns out to be more important than spatial information. This paper proposes a logistic model for the degradation of the normal information resulting from the quantisation of the vertex coordinates. The mesh is degraded by the randomization of each vertex coordinate after its t -th significant bit. The normal degradation is computed as a weighted average of the angle differences between the normals of the original triangles and the corresponding degraded triangles. The proposed model is validated experimentally. As an application, we use the proposed logistic model to estimate suitable levels of quantisation for 3D triangle meshes.