[comp.graphics] Renderman patch mesh question

nth@cs.brown.edu (Nate Huang) (07/03/90)

When rendering a patch mesh in Renderman with wrapping in the
u-direction, and with each u-row of points co-planar, one obtains a
sort of cylindrical tube. (These are commonly called objects of
extrusion or duct objects)  Suppose I wish to add endcaps to the
object.  Is there a nice way to accomplish this in Renderman?

When adding, say, the top cap, one can make an  nu X 2  patch mesh
with the first u-row being the top u-row in the original mesh, and the
second u-row all being the same point, a point enclosed within the top
u-row of points.  This will only work, however, if the top u-row of
points, when connected in succession, form a concave polygon.  Can
anyone offer a solution if the top u-row points form a convex polygon?

Nate
______________________________________________________________________________
Nate Huang             "52nd Street was a mother - and when I say mother,
nth@cs.brown.edu        I don't mean motherfucker.  But it was that too."
..!brunix!nth                                           -Dizzy