Fix T75936: Alembic, allow exporting of invisible objects

Add a new depsgraph builder class that includes invisible objects and
use that in the Alembic exporter.

Alembic supports three options for visibility, "visible", "inherited",
and "hidden". This means that parents can be hidden and still have
visible children (contrary to USD, where invisibility is used to prune
an entire scene graph subtree). Because of this, the visibility is
stored on the transform node, as that represents the Object in Blender
and thus keeps the Alembic file as close to Blender's own structure as
possible.

Reviewed By: Sergey

Differential Revision: https://developer.blender.org/D8595

1 files changed, 6 insertions, 0 deletions

diff --git a/source/blender/depsgraph/DEG_depsgraph_build.h b/source/blender/depsgraph/DEG_depsgraph_build.h
index 50f22b00028..dd52c97e03f 100644
--- a/source/blender/depsgraph/DEG_depsgraph_build.h
+++ b/source/blender/depsgraph/DEG_depsgraph_build.h
@@ -56,6 +56,12 @@ void DEG_graph_build_from_view_layer(struct Depsgraph *graph,
                                      struct Scene *scene,
                                      struct ViewLayer *view_layer);
 
+/* Build depsgraph for all objects (so also invisible ones) in the given view layer. */
+void DEG_graph_build_for_all_objects(struct Depsgraph *graph,
+                                     struct Main *bmain,
+                                     struct Scene *scene,
+                                     struct ViewLayer *view_layer);
+
 /* Special version of builder which produces dependency graph suitable for the render pipeline.
  * It will contain sequencer and compositor (if needed) and all their dependencies. */
 void DEG_graph_build_for_render_pipeline(struct Depsgraph *graph,