Reference/Release Notes/4.0/Core


Blend File Compatibility


  • Custom Properties can now be defined from the UI to store references to other data-blocks (b3c7f3c8a9). Previously, this was only doable through Python API.

Library Overrides

  • Many fixes and improvements were made, as part of the Blender Studio's "WING IT!" production. (PR #109704)
    • Parenting-related Object properties (the parent inverse matrix, parent type, parent sub-target) will now be reset to the linked reference data when parent pointer itself is modified in library file and updated during resync process (9ed5177055, 4842424220).
    • Cleanup-code pruning unused liboverride operations during RNA diffing would not always work properly, leading to accumulated invalid operations that could, under certain circumstances, end up severely breaking especially collections/objects hierarchies of liboverrides (784d09a87c).
    • Resync Enforce tool would not always work properly with collections of IDs (affecting especially Collections/Objects relationships) (2dfbd653a0, 1c0ffa1e18).
    • Code trying to fix invalid liboverride hierarchies was over-enthusiastic, which could pull data out of their valid original hierarchy into some more local, undesired one when production files start to become messy (bf93fb0f46).
    • Handling of lookup of items in RNA collections has been improved, to alleviate issues when there are name collisions between items (a05419f18b).
    • As a second approach to work around issue described above, changes were made to liboverride IDs naming, such that when created, they either get the exact same name as their linked reference, or they get a name that does not collide with any other linked override reference (b9becc47de, e11da03e7a).

Breaking Changes

  • The Depth pass support was removed from OpenEXR (the non-multilayer case) and Iris (e1b60fdb91)
  • Unused linked data is no longer kept when saving and re-opening a blendfile. This was already partially the case in previous releases.
    • The 'Fake User' setting is now fully irrelevant for linked data, and systematically cleared on load or link.
    • When an unused (as in, having zero users) linked data-block needs to be kept in a blendfile, users are expected to reference them through a Custom Property (e.g. from a Scene, Collection or Object data-block).
    • See #106321 and the related commits b3c7f3c8a9 and f052b18a65.
  • Keep some animation data from library overrides when no animation data existed originally in the linked reference, but it got added later on in the library file. Previously, any change related to animation done in the liboverride data would have been lost (#110067, PR #110900, f188d6709f).