Is there some way to make available the co-ordinates comprising an 
objects surface - or perhaps more generally, a way to pass POV-ray a 
spline and have it generate arbitrary points on that spline's surface?

I'm working on a simple macro and I need some way to figure out the 
distance between a point on a spline and the line stretching from that 
spline's start to end point.

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In article <406b8af6$1@news.povray.org>,
 Howard Kern <how### [at] hotmailcom> wrote:

> Is there some way to make available the co-ordinates comprising an 
> objects surface -

No. POV-Ray doesn't even know the points on the surface of an object 
until it does a ray test against it. Since there are infinitely many 
such points, and a really, really big number of points that can be 
uniquely represented by POV-Ray vectors, I don't think this is what 
you're asking. Maybe you're under the mistaken impression that POV-Ray 
tessellates objects to meshes internally, this is only done for height 
fields and bicubic patches.


> or perhaps more generally, a way to pass POV-ray a 
> spline and have it generate arbitrary points on that spline's surface?

That's possible. A more detailed answer would require more information 
to start with. You might find what you want on these newsgroups, several 
people have written includes and macros for this purpose:

http://members.home.nl/seedseven/param.html
<http://news.povray.org/povray.binaries.scene-files/thread/%3C3fb73d9e@ne
ws.povray.org%3E/>


> I'm working on a simple macro and I need some way to figure out the 
> distance between a point on a spline and the line stretching from that 
> spline's start to end point.

Well, that's quite easy, and doesn't have anything to do with object 
surfaces or even splines. You're just finding the distance between a 
point and a line segment.

<http://news.povray.org/povray.advanced-users/thread/%3C3a42753b@news.pov
ray.org%3E/>

-- 
Christopher James Huff <cja### [at] earthlinknet>
http://home.earthlink.net/~cjameshuff/
POV-Ray TAG: <chr### [at] tagpovrayorg>
http://tag.povray.org/

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