[x3d-public] Extrusions, take 3, coincident points

[Alekseyev, Vsevolod (NIH/NIAID) [E]]

>> 3) When the spine goes (0,0,0)-(1,1,0)-(1,1,0)-(1,1,0)-(2,0,0), what is the CSP for the three middle points?

> Hopefully the wording above covers this case of coincident points, at least for SCP (other animation issues may vary).  What do you think?

The spec says the coincident points will have the same CSP, but it doesn't say where will it come from. From point #2? #3? #4? A straightforward application of the CSP generation rules will produce different results for #2 and #4, and will give a division by zero if applied to #3.

http://www.web3d.org/wiki/index.php/Extrusion_Edge_Cases