it's in share/extensions/perspective.py, but how can you combine curved sides with perspective? Isn't it mutually exclusive?
Sorry for asking, I actually just found the envelope effect in summersnight.py. However, on first sight the envelope and the perspective script in perspective.py do seem to implement the same effect with different algorithms, the result is just rotated by 90 degrees...
Why would perspective and bezier curves be mutually exclusive? Maybe I misunderstood the concept (does someone remember what the sample looked like?), but the wiki page talks about envelopes and bezier nodes, if only for the more distant future.
http://wiki.inkscape.org/wiki/index.php/PerspectiveObject
Of course, with curved edges it won't be one of these boring Euclidean type linear perspectives, but you can do those with common 3D software anyway, right? ;)
Thanks and cheers, Gerrit