Tim Nikias wrote:
> Hey Rune! Nice to hear from you! :-)
> 
> 
>>How about creating a bezier patch for each quad? Then the subdivision
> 
> level
> 
>>can easily be controlled. And there are macros that take exactly a 2d
> 
> array
> 
>>of points and create a bezier patch "cloth" from them, automatically
>>creating all but the corner control points in the process (the corner
> 
> points
> 
>>being the ones that comes from the original 2d array).
> 
> SNIP
> 
> I thought about that and actually tried that when fiddling with bilinear
> interpolation. I think I could come up with an implementation, shouldn't be
> too difficult: calculate the control-nodes on the edges first and then
> interpolate among the neighbours to get the inner control points (of course
> keeping in mind that neighbouring patches need to have the same angle to the
> edge to keep the edges smooth).
An internal representation where at every node you record the x,y and z
position plus the derivatives in the u and v direction plus the second
derivative in the uv direction (a set that can be used to create a
smooth surface using Hermite polynomials) can uniquely be converted to a
smooth bicubic patch. I only mention this because it might be a more
natural set of parameters to work with during computation.

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