Remove REST transform influence in skeleton bones

* Animations and Skeletons are now pose-only.
* Rest transform is kept as reference (when it exists) and for IK
* Improves 3D model compatibility (non uniform transforms will properly work, as well as all animations coming from Autodesk products).

2 files changed, 7 insertions, 14 deletions

diff --git a/modules/fbx/data/fbx_skeleton.cpp b/modules/fbx/data/fbx_skeleton.cpp
index 3dc163964c..11eed2576f 100644
--- a/modules/fbx/data/fbx_skeleton.cpp
+++ b/modules/fbx/data/fbx_skeleton.cpp
@@ -104,6 +104,13 @@ void FBXSkeleton::init_skeleton(const ImportState &state) {
 		print_verbose("working on bone: " + itos(bone_index) + " bone name:" + bone->bone_name);
 
 		skeleton->set_bone_rest(bone->godot_bone_id, get_unscaled_transform(bone->node->pivot_transform->LocalTransform, state.scale));
+		{
+			Transform3D base_xform = bone->node->pivot_transform->LocalTransform;
+
+			skeleton->set_bone_pose_position(bone_index, base_xform.origin);
+			skeleton->set_bone_pose_rotation(bone_index, base_xform.basis.get_rotation_quaternion());
+			skeleton->set_bone_pose_scale(bone_index, base_xform.basis.get_scale());
+		}
 
 		// lookup parent ID
 		if (bone->valid_parent && state.fbx_bone_map.has(bone->parent_bone_id)) {
diff --git a/modules/fbx/editor_scene_importer_fbx.cpp b/modules/fbx/editor_scene_importer_fbx.cpp
index e90eab522f..879f281292 100644
--- a/modules/fbx/editor_scene_importer_fbx.cpp
+++ b/modules/fbx/editor_scene_importer_fbx.cpp
@@ -1227,20 +1227,6 @@ Node3D *EditorSceneImporterFBX::_generate_scene(
 										AssetImportAnimation::INTERP_LINEAR);
 							}
 
-							// node animations must also include pivots
-							if (skeleton_bone >= 0) {
-								Transform3D xform = Transform3D();
-								xform.basis.set_quaternion_scale(rot, scale);
-								xform.origin = pos;
-								const Transform3D t = bone_rest.affine_inverse() * xform;
-
-								// populate	this again
-								rot = t.basis.get_rotation_quaternion();
-								rot.normalize();
-								scale = t.basis.get_scale();
-								pos = t.origin;
-							}
-
 							if (position_idx >= 0) {
 								animation->position_track_insert_key(position_idx, time, pos);
 							}