1 Commits

Author SHA1 Message Date
Aras Pranckevicius
cc741fbf99 IO: New FBX importer (C++, via ufbx)
Adds a C++ based FBX importer, using 3rd party ufbx library (design task:
#131304). The old Python based importer is still there; the new one is marked
as "(experimental)" in the menu item. Drag-and-drop uses the old Python
importer; the new one is only in the menu item.

The new importer is generally 2x-5x faster than the old one, and often uses
less memory too. There's potential to make it several times faster still.

- ASCII FBX files are supported now
- Binary FBX files older than 7.1 (SDK 2012) version are supported now
- Better handling of "geometric transform" (common in 3dsmax), manifesting
  as wrong rotation for some objects when in a hierarchy (e.g. #131172)
- Some FBX files that the old importer was failing to read are supported now
  (e.g. cases 47344, 134983)
- Materials import more shader parameters (IOR, diffuse roughness,
  anisotropy, subsurface, transmission, coat, sheen, thin film) and shader
  models (e.g. OpenPBR or glTF2 materials from 3dsmax imports much better)
- Importer now creates layered/slotted animation actions. Each "take" inside
  FBX file creates one action, and animated object within it gets a slot.
- Materials that use the same texture several times no longer create
  duplicate images; the same image is used
- Material diffuse color animations were imported, but they only animated
  the viewport color. Now they also animate the nodetree base color too.
- "Ignore Leaf Bones" option no longer ignores leaf bones that are actually
  skinned to some parts of the mesh.
- Previous importer was creating orphan invisible Camera data objects for
  some files (mostly from MotionBuilder?), new one properly creates these
  cameras.

Import settings that existed in Python importer, but are NOT DONE in the new
one (mostly because not sure if they are useful, and no one asked for them
from feedback yet):

- Manual Orientation & Forward/Up Axis: not sure if actually useful. FBX
  file itself specifies the axes fairly clearly. USD/glTF/Alembic also do
  not have settings to override them.
- Use Pre/Post Rotation (defaults on): feels like it should just always be
  on. ufbx handles that internally.
- Apply Transform (defaults off, warning icon): not sure if needed at all.
- Decal Offset: Cycles specific. None of other importers have it.
- Automatic Bone Orientation (defaults off): feels like current behavior
  (either on or off) often produces "nonsensical bones" where bone direction
  does not go towards the children with either setting. There are discussions
  within I/O and Animation modules about different ways of bone
  visualizations and/or different bone length axes, that would solve this
  in general.
- Force Connect Children (defaults off): not sure when that would be useful.
  On several animated armatures I tried, it turns armature animation
  into garbage.
- Primary/Secondary Bone Axis: again not sure when would be useful.

Importer UI screenshots, performance benchmark details and TODOs for later
work are in the PR.

Pull Request: https://projects.blender.org/blender/blender/pulls/132406
2025-04-16 09:55:00 +02:00