View source for Reference/Release Notes/2.79/Alembic

= Blender 2.79: Alembic =

The Alembic import & export has been improved, both in stability and compatibility (revisions {{GitCommit|56cfd3d5a7d}}..{{GitCommit|c684fab8a6ea}})

==== Fixes ====

* Fixed errors in matrix conversion (most Alembic files use Y=up, while Blender uses the more sensible Z=up).
* Re-implemented part of the importer, so that it has to guess less, improving compatibility with non-Blender generated files (fixes [https://developer.blender.org/T50403 T50403])
* The importer is now more lenient to unknown types.
* Improved performance by removing some unnecessary computations.
* Prevented crash when cancelling import ({{GitCommit|3748ca432d2}} & {{GitCommit|43a910abce5}}).
* Fixed "flat" import (i.e. all objects in world coordinates, no parenting) ({{GitCommit|642728b3395a}})
* Fixed [https://developer.blender.org/T50227 T50227]: Alembic uv export/load issue ({{GitCommit|699a3e2498}})
* Added simple unit tests ({{GitCommit|6af131fa5}})
* Greatly improved performance of curve/hair import ({{GitCommit|e12c3110024dc}})
* Changing cache modifier path no longer discards object paths ({{GitCommit|9c02990ac13a}})
* Meshes with animation data are now saved on every frame ({{GitCommit|6715bfee92e72d}}, [https://developer.blender.org/T51351 T51351]). This allows you to change a mesh procedurally, for example using a Python script, and have it exported every frame, simply by ensuring the mesh has some animation data on it.
* Support for sub-frame sampling ({{GitCommit|35f4abcf53dad}} and {{GitCommit|24a0b332e2a72}}).
* Fixed missing material assignment when an animated mesh changed vertex count ({{GitCommit|45d7513f84bd3f}}).
* Importing now takes the "inherit transform" flag into account correctly when constructing parent-child relationships ({{GitCommit|32edfd53d978b34}} and [https://developer.blender.org/T52022 T52022]).
* Sequences of Alembic files are now handled properly ({{GitCommit|0900914d9644}} and [https://developer.blender.org/T51820 T51820]).

==== New Features ====

* Exporting of linked-in dupli-groups is now possible. This supports the common character animation workflow used at the Blender Institute, where a character, its rig, and the custom bone shapes are all part of a group. This group is then linked into the scene, the rig is proxified and animated. Such a group can now be exported. Use "Renderable objects only" in the export options to prevent writing the custom bone shapes to the Alembic file. ({{GitCommit|ebb30451140}}, [https://developer.blender.org/T50688 T50688])
* Exporting hair & particle systems is now optional. The export still takes more time with disabled hair than when there is no hair, as the particle systems themselves aren't disabled during the export. It's only the writing to the Alembic file that's skipped. ({{GitCommit|b148ac5cf77a869bc}})
* The Import and Export operators now take a new flag <tt>as_background_job</tt>, which is <tt>True</tt> by default. When set to <tt>False</tt>, the operator will block Blender during the import. This allows Blender scripts to perform tasks after the import/export has completed. ({{GitCommit|2dac8b3ee043}})
* Empties can now also be exported to Alembic (both static and animated) ({{GitCommit|9b3e3d4defc66}}).
* Exporting simple child hairs is now possible. ({{GitCommit|6ed15c5a411}})
* Added support for face-varying vertex colours (read: compatibility with Houdini) ({{GitCommit|7b25ffb618dd}}, [https://developer.blender.org/T51534 T51534])
* Support for empty meshes (which can get vertices later in their animation) ({{GitCommit|6715bfee92e72d}}, [https://developer.blender.org/T51351 T51351])
* Loading an Alembic file stored in the obsolete HDF5 format will now give an error message telling you the format is not supported in Blender ({{GitCommit|9dadd5ff937}}, [https://developer.blender.org/T51292 T51292]). Such files can be converted using [https://github.com/alembic/alembic/tree/master/bin/AbcConvert AbcConvert]. The current format, Ogawa, is [http://exocortex.com/blog/alembic_is_about_to_get_really_fast 4x to 25x faster than HDF5], and was [https://groups.google.com/forum/#!topic/alembic-discussion/FTG1HuuO_qA introduced almost four years ago].