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Andrew (ajohnson223)
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User Since
Oct 24 2019, 12:24 PM (76 w, 5 d)

Recent Activity

Sep 14 2020

Andrew (ajohnson223) awarded D8868: Import/Export: Wavefront Obj Mtl Overhaul (Improved Compatibility and PBR Extension Support) a Love token.
Sep 14 2020, 8:10 AM · Rendering, Import/Export

Nov 6 2019

Andrew (ajohnson223) added a comment to T71246: Mesh normals handling in Alembic.

Thanks again @Sybren A. Stüvel (sybren), I'm sure it's working nicely but i'll put it through its paces soon.

Nov 6 2019, 11:03 AM · Alembic, BF Blender
Andrew (ajohnson223) awarded rBb0e7a1d4b492: Alembic: improved import/export of mesh normals a Love token.
Nov 6 2019, 11:01 AM
Andrew (ajohnson223) added a comment to T71246: Mesh normals handling in Alembic.

I got some clarification on kVaryingScope vs. kVertexScope here:

Nov 6 2019, 10:50 AM · Alembic, BF Blender
Andrew (ajohnson223) added a comment to T71246: Mesh normals handling in Alembic.

@Sybren A. Stüvel (sybren) Hmm, I actually thought Alembic kVertexScope == Blender Vertex Normals, rather than kVaryingScope.

Nov 6 2019, 10:29 AM · Alembic, BF Blender

Nov 1 2019

Andrew (ajohnson223) added a comment to T71246: Mesh normals handling in Alembic.

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.

Nov 1 2019, 9:46 AM · Alembic, BF Blender
Andrew (ajohnson223) added a comment to T71246: Mesh normals handling in Alembic.

Blender has no concept of custom vertex normals, only loops (aka face corners) ones. Checking for 'equal to auto normals' might be possible, but won't be a cheap process, and not so sure it would be worth is… If you export your normals, even as vnors, then one can expect them to have some importance?

Nov 1 2019, 9:28 AM · Alembic, BF Blender
Andrew (ajohnson223) added a comment to T71246: Mesh normals handling in Alembic.

I would change that point on new import behavior:

The Alembic mesh contains vertex normals → mark mesh as smooth.

… to The Alembic mesh contains vertex normals → use as custom loop normals, and enble Auto Smooth to have Blender actually use them.

Think you will find some cases where custom normals (e.g. for toon shading effects) have been stored as vertex normals, because no 'hard edge' was desired, but normal directions others than default ones were used. Note that BKE has an API to set custom normals from per-vertex values as well. That’s what FBX is doing at least.

Nov 1 2019, 9:17 AM · Alembic, BF Blender
Andrew (ajohnson223) added a comment to T71130: Alembic split normal export issue.

Looks great! :) Thanks.

Nov 1 2019, 4:43 AM · Alembic, BF Blender
Andrew (ajohnson223) awarded T71246: Mesh normals handling in Alembic a Love token.
Nov 1 2019, 4:42 AM · Alembic, BF Blender

Oct 30 2019

Andrew (ajohnson223) added a comment to T71130: Alembic split normal export issue.

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...

Oct 30 2019, 4:59 PM · Alembic, BF Blender
Andrew (ajohnson223) added a comment to T71130: Alembic split normal export issue.

@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).

Oct 30 2019, 4:55 PM · Alembic, BF Blender
Andrew (ajohnson223) added a comment to T71130: Alembic split normal export issue.

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:

Oct 30 2019, 2:36 PM · Alembic, BF Blender
Andrew (ajohnson223) added a comment to T71130: Alembic split normal export issue.

@Sybren A. Stüvel (sybren) Thanks, but can there please be some additional clarification on this?

Oct 30 2019, 2:20 PM · Alembic, BF Blender

Oct 27 2019

Andrew (ajohnson223) updated subscribers of T71130: Alembic split normal export issue.

Also, calling out @Sybren A. Stüvel (sybren) since he appears to be the resident alembic dev...

Oct 27 2019, 11:42 AM · Alembic, BF Blender
Andrew (ajohnson223) created T71130: Alembic split normal export issue.
Oct 27 2019, 11:41 AM · Alembic, BF Blender

Oct 24 2019

Andrew (ajohnson223) added a comment to T69058: Alembic integration improvements.
Oct 24 2019, 12:32 PM · Alembic, BF Blender