In article <slr### [at] fwicom>, ron### [at] povrayorg 
wrote:

> Even linear spline prisms?  Whyever for?  There's a simple procedure to
> determine the distance of a point from an arbitrary polygon[1].  The 
> proximity is then the minimum over all the edges and the two caps of the 
> prism.

Because I didn't know this algorithm. :-)
Hmm, does this take the caps into account? It looks like an infinitely 
long prism(or proximity to a polygon in a 2D plane).
When mesh proximity is implemented, it should be possible to do some 
shapes fairly accurately by simply tesselating them. Prisms should be 
fairly easy to tesselate...


> Beware, though: the proximity function may be continuous, but it is not
> continuously differentiable, and that might matter to the isosurface 
> solver.

It should still give better results than the raw object pattern in most 
cases, and better than a blurred object pattern(since the only way I can 
figure out to do the blur gives several "steps" of values).
BTW, what exactly do you mean by "continuously differentiable"? Do you 
mean that the function may be continuous but the derivative may not be? 
Where would the function "break"?

-- 
Christopher James Huff
Personal: chr### [at] maccom, http://homepage.mac.com/chrishuff/
TAG: chr### [at] tagpovrayorg, http://tag.povray.org/

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