Created 18 years ago2006-05-22 21:55:47 UTC by stoopdapoop
3ds max has its origins in the mid-1980?s 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 1990?s. Due to this historical evolution of the software, 3ds max still uses the 1980?s 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 and long ?sliver? triangles which are common from data obtained from meshed CAD solids data. Several suggestions are available. First, for the problematic mesh model in question, select it inside 3ds max and apply a ?Smooth? object-space modifier to it; enable the ?Auto-smooth? and optionally enable the ?Prevent Indirect Smoothing? checkboxes. Alternatively, what you need to do is break apart the problematic mesh model so that the parts which are smoothed and the parts which have abrupt angular changes are in two different mesh models; this latter suggestion is rarely, if ever, required to be done. Even though 3ds max uses smoothing groups it still does provide ?32 bitmaks? per vertex (internally within its database) and thus provides some good freedom to approximate the original vertex normals of the CAD data with the new smoothing group flags per vertex; this should be compared to Lightwave which only has a single smoothing cut-off angle per-material-per-mesh object and thus has much less freedom to recreate the smoothing properly. - Updated: October 19, 2004I got this from http://www.okino.com/faqs_output_dir/12.htm