CompuServe Messages

Skinning

    11-Dec-94 15:27:49
Sb: #140410-Skinning
Fm: M. G. BATCHELOR 71532,1214
To: Marvin Nauman 75543,1275
Marvin, <<(I hope that I have the right Batchelor)>> My CIS address is 71532,1214. What problems are you having with joints ? Note that the techniques I mentioned in the text for the Branch & Female meshes can be very difficult or impossible to implement with success….and every circumstance is different. Start by experimenting with making simple "inner loops" of Skin, similar to the Branch example. Note that this can make certain texture mapping difficult too. Just visualize that you're stretching a flexible closed-loop of "Skin" suface, draped around the Slices' perimeters from the starting CS to the end….following along the "path" implied by the sequence of Slices. If the vertices' ordering rotates from one CS to the next, then the Skinned surface will twist. If they rotate a lot, you can pinch (wreck) the surface. By Moving, Scaling, & Rotating CS's, you can "hide" folding-back sections of Skin inside the visible outer surface. This lets you (in some cases) trace back a path from a branch, back to the main "trunk" of the Skinned object. Just as attempting to Skin non-lofted objects, this technique really isn't supposed to work. But in both cases, there are exceptions. Your entire scene/animation will have to be very contrived to use this. You'll need to compose your scenes & frame your shots to avoid seeing surface discontinuities, or provide some "misdirection" to lead the eyes away from problem areas. Use lighting & material definitions to help hide objectionable seams. For example, using an Ambient (material) value lower than the Diffuse value will just accentuate the seam….avoid this. BILL