In article <3c7aaf24@news.povray.org>,


> Possibly. But this is not of interest since almost each triangle in the mesh
> has a different texture and (would have) therefore different interiors.

Think about what this object would be like...there is nothing in the 
real world remotely like this. The closest thing would be an ior 
variable over space, which POV is incapable of doing (and which would 
take a huge amount of time if it was capable). Are you sure you need for 
each triangle to have its own interior?


> I don't understand why the same effect (called interior and it's media)
> behaves completely different on different primitives. In a hollow sphere it
> works as expected. If POV allows the same statement in a triangle, I expect
> this behavior too. But nope. It's completely different.

Actually, the problem is that it's the same. Media operates over the 
interior of the object. A sphere has a finite interior, defined by the 
area between the point where the ray enters the sphere and where it 
exits. Triangles don't...after the ray enters the triangle, it is 
inside. Meshes are in the middle, after hitting the mesh, the ray is 
inside until it hits another part of the mesh.


> As you can see clearly: in case of the triangle the media is only visible if
> there is something BEHIND it. This is not the case for the spheres.
> Where's the clue?

There is an object behind it. That gives POV a finite interval to sample 
the media in. In the areas where only the background is visible, the ray 
goes off into infinity, and POV can't sample it. Put a big, hollow 
sphere around your scene, and things will be more predictable, though 
still not realistic...lone triangles aren't very useful for media 
containers.


> Unfortunately this would overload my PC. And possibly even yours. Nature is
> more complex than any computer avaliable today could handle.... So I need
> some simplification. And in fact we all use simplifications like normals,
> textures and all the nice POV features. Normals are used to replace
> tiny-detail-modelling (every object should have the SHAPE and not a
> mathematical shape with normals stick on it). Similar situation for
> textures.

You don't have to duplicate nature entirely, just use closed meshes. 
Closing the mesh shouldn't add that much in complexity.

-- 
Christopher James Huff <chr### [at] maccom>
POV-Ray TAG e-mail: chr### [at] tagpovrayorg
TAG web site: http://tag.povray.org/

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