- User Since
- Oct 24 2019, 12:24 PM (76 w, 5 d)
Sep 14 2020
Nov 6 2019
Thanks again @Sybren A. Stüvel (sybren), I'm sure it's working nicely but i'll put it through its paces soon.
I got some clarification on kVaryingScope vs. kVertexScope here:
@Sybren A. Stüvel (sybren) Hmm, I actually thought Alembic kVertexScope == Blender Vertex Normals, rather than kVaryingScope.
Nov 1 2019
FWIW, so far Blender has had the "vertex normals → shade smooth" approach, and I haven't seen any bug report about this behaviour as of yet.
Looks great! :) Thanks.
Oct 30 2019
For such an approach to work and allow blender to have "normals idempotence" with abc files that it outputs and re-imports, blender would need to be (optionally?) capable of generating smooth normals on the fly for objects that don't have normals specified, whenever an abc is imported. Maybe it already has that, but I'm not sure offhand...
@Sybren A. Stüvel (sybren) Thanks! Makes sense, I think that's a valid approach. Though one downside of saving face varying for every object in the scene -- even for objects that have smooth normals -- is that it could significantly increase the size of the output abc file. Another potentially bigger problem, is that upon re-import, if the tool ingesting that abc is not smart enough to merge identical face-varying normals for a vertex into a vertex-varying normal, that "normals bloat" could make its way to the GPU and really hinder render performance. Imagine a scene filled with thousands of smooth-normaled spheres. Exporting that and reimporting that -- even with normals -- should ideally not result in face-varying normals -- which consume many times the space of vertex-varying ones -- making their way to the GPU memory (or cpu memory if dealing with a cpu renderer).
For posterity, the solution to preserve normals within an abc such that they match the blend file is to do the following prior to export:
@Sybren A. Stüvel (sybren) Thanks, but can there please be some additional clarification on this?
Oct 27 2019
Also, calling out @Sybren A. Stüvel (sybren) since he appears to be the resident alembic dev...