Importing my CAD model directly into 3ds max shows smoothing anomalies (banding). Why?
3ds max has its origins in the mid-1980s program called CAD-3D written by Tom Hudson on the Atari ST computer. It and other Antic software products were culled together and ultimately became the 3D Studio product line developed by the Yost Group and Autodesk. 3D Studio evolved into 3ds max in the mid 1990s. Due to this historical evolution of the software, 3ds max still uses the 1980s concept of smoothing groups to represent the smoothing on mesh objects rather than the more ideal, accurate and modern vertex normals method. Smoothing groups are just an approximation of the original smoothing information contained in the source CAD model. Smoothing groups have problems representing the original smoothing for CAD objects which share smooth and abrupt angles within the same mesh model and on the same set of triangles. The problems will manifest themselves as black bands as well as visible seams along triangle boundaries. In addition, 3ds max has inherently had problems rendering very thin
