Alembic: export animated vertex colors #88074

New Issue

Sybren A. Stüvel · 2021-05-06T12:17:24+02:00

Sybren A. Stüvel commented

2021-05-06 12:17:24 +02:00

The Alembic exporter currently (Blender 3.0 alpha, master @ 42e350b9a5) exports vertex colors only on the first exported frame. It would be nice if it would do this on every frame.

This task was created so that D8397: Alembic add option to write UVs on every frame can be limited to only exporting animated UV maps. Applying the same approch to vertex colors crashes the Alembic exporter:

terminate called after throwing an instance of 'Alembic::Util::v12::Exception'
  what():  OCompoundProperty::init()
ERROR: EXCEPTION:
Already have a property named: dp_paintmap

This is due to the write_mcol() function creating a new C++ object on every call, instead of keeping a reference to a single object. This causes the Alembic exporter to finalise the written property after a single frame, and then crash when a new property with the same name is created. To reproduce this crash, apply this patch:

diff --git a/source/blender/io/alembic/exporter/abc_writer_mesh.cc b/source/blender/io/alembic/exporter/abc_writer_mesh.cc
index 29b29324ee3..b7d029683a3 100644
--- a/source/blender/io/alembic/exporter/abc_writer_mesh.cc
+++ b/source/blender/io/alembic/exporter/abc_writer_mesh.cc
@@ -364,7 +364,7 @@ void ABCGenericMeshWriter::write_arb_geo_params(struct Mesh *me)
     return;
   }
 
-  if (frame_has_been_written_ || !args_.export_params->vcolors) {
+  if (!args_.export_params->vcolors) {
     return;
   }

and export the cube from this example file. The Python console already has a command set up, so you only need to run it by pressing {key Enter} there.

test_animated_vcolors.blend

The Alembic exporter currently (Blender 3.0 alpha, master @ 42e350b9a5) exports vertex colors only on the first exported frame. It would be nice if it would do this on every frame. This task was created so that [D8397: Alembic add option to write UVs on every frame](https://archive.blender.org/developer/D8397) can be limited to only exporting animated UV maps. Applying the same approch to vertex colors crashes the Alembic exporter: ``` terminate called after throwing an instance of 'Alembic::Util::v12::Exception' what(): OCompoundProperty::init() ERROR: EXCEPTION: Already have a property named: dp_paintmap ``` This is due to the `write_mcol()` function creating a new C++ object on every call, instead of keeping a reference to a single object. This causes the Alembic exporter to finalise the written property after a single frame, and then crash when a new property with the same name is created. To reproduce this crash, apply this patch: ``` diff --git a/source/blender/io/alembic/exporter/abc_writer_mesh.cc b/source/blender/io/alembic/exporter/abc_writer_mesh.cc index 29b29324ee3..b7d029683a3 100644 --- a/source/blender/io/alembic/exporter/abc_writer_mesh.cc +++ b/source/blender/io/alembic/exporter/abc_writer_mesh.cc @@ -364,7 +364,7 @@ void ABCGenericMeshWriter::write_arb_geo_params(struct Mesh *me) return; } - if (frame_has_been_written_ || !args_.export_params->vcolors) { + if (!args_.export_params->vcolors) { return; } ``` and export the cube from this example file. The Python console already has a command set up, so you only need to run it by pressing {key Enter} there. [test_animated_vcolors.blend](https://archive.blender.org/developer/F10056245/test_animated_vcolors.blend)

Sybren A. Stüvel commented

2021-05-06 12:17:24 +02:00

Changed status from 'Needs Triage' to: 'Confirmed'

Sybren A. Stüvel commented

2021-05-06 12:17:24 +02:00

Added subscribers: @dr.sybren, @CodyWinchester

blender-admin commented

2021-11-05 14:59:03 +01:00

This issue was referenced by 4e2478940e

This issue was referenced by 4e2478940eb8803f28bfd7361ea3ff7dd83cd247

Sybren A. Stüvel commented

2022-09-27 10:17:42 +02:00

Changed status from 'Confirmed' to: 'Resolved'

Sybren A. Stüvel closed this issue

2022-09-27 10:17:42 +02:00

Sybren A. Stüvel self-assigned this 2022-09-27 10:17:42 +02:00

Sybren A. Stüvel commented

2022-09-27 10:17:42 +02:00

Marking as resolved, this should have been closed when D11278: Alembic: Allow exporting of animated vertex colors landed.

Marking as resolved, this should have been closed when [D11278: Alembic: Allow exporting of animated vertex colors](https://archive.blender.org/developer/D11278) landed.

Thomas Dinges added this to the 3.4 milestone 2023-02-07 19:01:34 +01:00

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Alembic: export animated vertex colors #88074