Alembic import: option to always add a cache reader

The current behavior of the Alembic importer is to only create a
`MeshSequenceCache` modifier or a `Transform Cache` constraint to imported
objects if they have some animated properties.

Since static objects do not have a cache reader, when reloading files those
objects are not updated. Currently, the only way to properly reload a file
because of this is to reimport it.

This adds an option to the importer to always add a cache reader, even if
there is no animated data, to ensure that all objects coming from Alembic
archive are linked to them and updated properly upon reloads.

Reviewed by: brecht, sybren

Ref D10197.

1 files changed, 2 insertions, 0 deletions

diff --git a/source/blender/io/alembic/intern/alembic_capi.cc b/source/blender/io/alembic/intern/alembic_capi.cc
index b94b75b2216..deb945b767c 100644
--- a/source/blender/io/alembic/intern/alembic_capi.cc
+++ b/source/blender/io/alembic/intern/alembic_capi.cc
@@ -663,6 +663,7 @@ bool ABC_import(bContext *C,
                 int sequence_len,
                 int offset,
                 bool validate_meshes,
+                bool always_add_cache_reader,
                 bool as_background_job)
 {
   /* Using new here since MEM_* functions do not call constructor to properly initialize data. */
@@ -681,6 +682,7 @@ bool ABC_import(bContext *C,
   job->settings.sequence_len = sequence_len;
   job->settings.sequence_offset = offset;
   job->settings.validate_meshes = validate_meshes;
+  job->settings.always_add_cache_reader = always_add_cache_reader;
   job->error_code = ABC_NO_ERROR;
   job->was_cancelled = false;
   job->archive = nullptr;