This fixes 4 bugs all conspiring to make the referenced SubD scenario
quite broken:
- When manually creating a MeshSequenceCache, the reading of edge and
vertex crease data was skipped. Fixed by reading crease data inside
the common `read_mesh` method.
- When importing an Alembic with animated edge or vertex crease data, a
MeshSequenceCache modifier was not being added to the object. This was
due to not checking the relevant crease properties and required adding
a specialized `has_animations` function.
- When importing animated vertex crease data, a duplicate `vertex_crease`
attribute would be created, breaking the animation. Fixed by using the
attribute API rather than custom data.
- The MeshSequenceCache scenario would call into the Alembic Mesh reader
which ended up referencing deallocated stack memory for the
ImportSettings. In release builds this would cause sporadic failures
because the value of `blender_archive_version_prior_44` would be
random. There was already a very old TODO for this and we finally
really needed to address it.
A new test was added which exports animated creases on two meshes and
re-imports them back in. It verifies that each mesh gets a
MeshSequenceCache modifier added and also ensures the values of the
creases are correct for all frames.
Pull Request: https://projects.blender.org/blender/blender/pulls/141646
cbb6cdf8d7