Things like missing directories are now properly checked for, rather than
crashing Blender.
This also adds support for relative paths when opening an ABC file.
It's now less confusing (for example, using nr_of_samples directly,
instead of using 1 / 1 / nr_of_samples). Might also have fixed a bug.
Also added unittests.
The old default values (start/end frame = 1) could have been an actually
desired setting (for example when exporting a non-animated model). To
make this worse, this was only interpreted as "start/end of the scene" by
the export operator when running interactively, but not when run from
Python.
By choosing INT_MIN as default it's highly unlikely that the interval
[start, end) was intended as actual export range.
The ABC_export and ABC_import functions both take a as_background_job
parameter, and return a boolean.
When as_background_job=true, returns false immediately after scheduling
a background job. This was the old behaviour of this function, which makes
it very hard for scripts to do something with the data after the import
or export completes.
When as_background_job=false, performs the export synchronously, and
returns true when the export was ok, and false if there were any errors.
This allows further processing.
The Scene.alembic_export() function is deprecated, and will be removed from
Blender 2.8 in favour of calling the bpy.ops.wm.alembic_export() operator.
As such, it has been hard-coded to the old background job behaviour.
The export is still slower than needed, as the particle systems themselves
aren't disabled during the export. It's only the writing to the Alembic
file that's skipped.
any object
There were a couple of crashes caused by stupid typos in
rB631af9f930d2fd2c76751204ff22239aa95f761d and
rB78ea06fea4a74181c25254ed72d50d8a743b6954, as well as a shamefull lack
of 'testing before committing' which only affect exporting.
One crash was due to using RNA_boolean_get instead of RNA_enum_get, the
other one was a tricky case of order of deletion happening in the
destructors of AbcExporter and ArchiveWriter.
Should not affect RC or release.
export.
This aligns the behaviour of the file selection with the other
exporters. The Alembic case would fail if the filepath did not have an
extension set.
Also set a default file name for the Alembic export operator in case the
Blender file was not saved before exporting.
All in all, this patch adds an Alembic importer, an Alembic exporter,
and a new CacheFile data block which, for now, wraps around an Alembic
archive. This data block is made available through a new modifier ("Mesh
Sequence Cache") as well as a new constraint ("Transform Cache") to
somewhat properly support respectively geometric and transformation data
streaming from alembic caches.
A more in-depth documentation is to be found on the wiki, as well as a
guide to compile alembic: https://wiki.blender.org/index.php/
User:Kevindietrich/AlembicBasicIo.
Many thanks to everyone involved in this little project, and huge shout
out to "cgstrive" for the thorough testings with Maya, 3ds Max, Houdini
and Realflow as well as @fjuhec, @jensverwiebe and @jasperge for the
custom builds and compile fixes.
Reviewers: sergey, campbellbarton, mont29
Reviewed By: sergey, campbellbarton, mont29
Differential Revision: https://developer.blender.org/D2060
