Shading: Fitting a smooth intensity surface (Q1902422)

The paper describes a very good alternative to the standard Gourand shading method for geometric models represented by polyhedral meshes with planar faces. Gourand shading leads to images whose intensity varies in a \(C^0\) fashion, i.e., intensities are the same along shared edges in the model but they are not \(C^1\) (derivative) continuous. The author uses the Powell-Sabin split for triangular meshes to construct intensity functions that are \(C^1\) continuous. This results in images with greatly reduced Mach band effects along the boundary edges in the mesh.