Wiz wrote: I would expect a "sensibly written" modeller to allow edges to carry infomation, so an edge could be labeled as smooth, or a crease, an edge, or a dart. .OBJ format as defined for Wavefront does carry that information: for each corner of each face there is a vn line which states the normal there (as well as a vt texture map coordinate), and also there are s lines which divide the object into "smoothing areas". But Poser ignores these vt and s lines, and they are not represented by anything in Poser mesh .RSR file format. I suspect that Bryce ignores them also. But if one angle is very sharp, then two of the edges start to look like parallel lines. Uhh. In my own attempt at writing a simple renderer (as used in my MAKEOBJ and FACES), when rendering a triangle face, I treat the face's normal as bring at right angles to the plane of the face, and I do not directly consider the directions of the edges. (If a face has more than 3 corners, I treat it a triangle at a time.) If I ever go as far as to program them to render with smoothing, I would likely put the normal at each vertex to the average of the normals to the faces that meet there. Would you like me to recommend a couple of good books or places where you can dig for some information on the basics? That would be useful. Please state the publishers and the ISBN numbers. This whole bit about corrupting the geometry by "unwelding" edges to control how they render is archaic. I know that, and it is a nuisance when mesh-editing the model. That is why I wish that Poser had a user-settable maximum smoothing angle like Bryce has. ... giving rise to the classic "spider web" artifacts. That likely depends on how likely it is that that particular cylinder-end or drum-end will ever be rendered with a pattern using the vt values (which in Bryce is called "parametric mapping"), rather than all the same color. In texture mapping as implemented in my MAKEOBJ, if I go from one face to another, the (equation for where on the texture map to read the color from) always changes continuously and not by steps, if all face-corners at the same vertex have exactly the same vt value (or point to the same entry in the vt table), so spider-web type breaks in the pattern should not occur. My release of MAKEOBJ includesd all of its source form.