But in SL and any polygonally-rendered computer graphics, any ring of polygons needs an extra set of vertices at the seam to avoid texture map problems. So you could say the torus ring in SL is not truly closed, and therefore just a cylinder bent into a circle.

Primitives with holes in them also violate the topological equivalence rule, strictly speaking. But in practice, you can really think of the hole as a negative space prim inside a simple genus zero prim and not worry about it.

It’s nice IMO when you can take hard math problems and say you don’t have to worry about them. Makes things nice and fast.

do you mean “torus”?

http://bitbucket.org/lindenlab/trunk/src/e2726e788831/indra/viewer/llface.cpp

I don’t know C++ but it looks fairly comprehensible ?

As I mentioned, if I had to do it again, I would eliminate the Face concept and just begin with simple projections of the same texture everywhere, applying special cases as decals.
The popping you’re seeing could be from some mismatch between faces and actual sides — maybe some optimization kicking in.

Sorry I couldn’t be of more help.

I am stuck on one single type – that is planar texture applied to the sides of a tapered or sheared box prim – it has to be planar to avoid texture tearing – but there is a shift in the planar numbers when the prim is tapered or sheared – the sloping side texture is offset and stretched. This needs to be corrected and it would be great to get the script to do it – but I can’t figure out how to measure the effect – it looks as thought the planar map is projected from a central point somwhere and distorts when the prim changes shape or proportions. Would love to understand this.

{PS – how I wish I had known about this site a year ago – great stuff

I did have a question as to why the ability to use more of the points isn’t available to the user? I enjoy making complex geometry, and would prefer making it in SL rather then sculpting it.

This would include a more practice (in my opinion) though more complex extrusion system. That would be more like you would find in 3D design software.

For 3, you get different texturing results depending on how you select paths and profiles for making spheres. There’s more than one choice. Convolving a semicircular profile around a circular path gives spherical coordinates. But you could also imagine a sphere built as a circle convoled over a straight line path that has its scale set such that the result is a sphere instead of a cylinder. That could be made to have a much better texture projection, especially for the poles.