Issue - Modifiers break per-face attributes (among others)

The way things work in RenderMan, you have a lot of flexibility to "tag" geometry with attributes of various types - colors, scalars, strings, normals, matrices, etc. You do this tagging at many levels: per-face, per-vertex, per-edge, etc. However, you do have to be consistent: if you provide (in this case) per-face colors for some faces, you must provide them for *all* faces. Polyhedron is doing that fine, but what's happening is that the subsequent ExtrudeFaces modifiers aren't assigning per-face colors for the new faces they create. So the RIB output produced by K-3D isn't valid in this case. The short-term workaround is to use the TagColors modifier with the "tag faces" property enabled, to assign colors to all the faces. I will add some sanity checking in our RIB output to catch this scenario and correct it. Longer-term, it's going to be a bear to fix all of the modifiers that aren't generating tags ... doh! But it'll have to be done. I will postpone it to after 0.6 because there are some other performance-related changes to k3d::mesh that will have an impact on the work.

Details

Id:
afe8a5c7a2db5849096010a7e4e37ffd246fc5de
Type:
Bugfix
Creation Time:
2009-05-19 03:51 UTC
Reporter:
Beverly L. Shead <bshead@k-3d.com>
Release:
1.0.0.0
Status:
Closed

Issue Log

2009-05-19 03:51 UTCBeverly L. Shead <bshead@k-3d.com>created
2009-08-02 22:47 UTCTimothy M. Shead <tshead@k-3d.com>assigned to release 1.0.0.0 from unassigned
2010-01-09 17:52 UTCTimothy M. Shead <tshead@k-3d.com>closed with disposition reorgThe generic mesh primitives introduced in K-3D 0.7 prevent this from happening.