In article <3d7c76e4@news.povray.org>, Warp <war### [at] tagpovrayorg> 
wrote:

>   Unless POV-Ray handles a union of triangles in a very special way (which
> I don't know if it does; I suppose not), then even one single instance of
> a mesh takes less memory than a union of triangles (because in a mesh
> vertex points shared by several triangles are stored only once, not once for
> each triangle, as I suppose happens with a union of triangles).

The mesh primitive also has a well optimized way of doing bounding 
calculations on individual triangles.

A union is a collection of shapes, the syntax of each shape is exactly 
the same as it would be outside of the union. A mesh is not a collection 
of triangle objects, it is a collection of triangle vertex, normal, and 
texture data, optimized for memory and speed. It is more of a 
"multi-triangle" than a group of triangles. Because of this, mesh 
triangles don't support the exact same syntax.

-- 
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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