In article <39920E80.B2D662D0@hotmail.com>, Pabs <pab### [at] hotmailcom> 
wrote:

> "object" pattern ? - probably would only work for solid objects'

The object pattern will only work for objects that are solid, and it 
isn't very friendly with the isosurface solving method. It is a "block 
pattern", and has only one of two states...basically meaning it has an 
infinite max_gradient. The isosurface algorithm can't easily cope with 
this.


> > Bicubic patches? Meshes? Polygons?
> >   What about infinite surfaces like planes and polys? An isosurface 
> >   can't be
> > infinite since it has to be contained by a finite object.
> 
> These may not work

Bicubic patches might be approximated with a function of some sort, 
though you might have to clip the resulting surface yourself. Polygons 
wouldn't be possible, but prisms would be. Plane, quadratic, poly, 
quartic, etc would work fine, they would just be clipped to the 
contained_by object. Meshes...I don't think there is an easy way to 
support meshes. Maybe if you used a sort of proximity pattern(optimized 
for meshes, of course)...


> >   You ideas are very good, though.
> 
> I agree

As do I...many of the object *could* have built in functions.
As for the existing built in functions, I really hope their syntax is 
changed if they are included. It is really non-standard, non-POV, and 
inconsistent.(Parameters in a vector?!? Function names in a string? 
Results affected by the size of the bounding box? Etc...)

-- 
Christopher James Huff - Personal e-mail: chr### [at] maccom
TAG(Technical Assistance Group) e-mail: chr### [at] tagpovrayorg
Personal Web page: http://homepage.mac.com/chrishuff/
TAG Web page: http://tag.povray.org/

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