README.md

@@ -87,9 +87,12 @@ This add-on allows you to add [SMPL-X](https://smpl-x.is.tue.mpg.de) skinned mes
   + Added Alembic export button
 + 20220315:
   + Speed up animation import time
-+ 20220328:
++ 20220326:
   + Added Unreal FBX export. Shape keys bake options can now be found in export dialog settings.
   + Fix unwanted duplicated animation sequence in FBX export
++ 20220613:
+  + Add option to import animation onto grounded rest pose armature
+  + Disable animation keyframe simplification for FBX export so that FBX animations match Alembic animations
 
 ## Contact
 + smplx-blender@tue.mpg.de

__init__.py

@@ -19,7 +19,7 @@
 bl_info = {
     "name": "SMPL-X for Blender",
     "author": "Joachim Tesch, Max Planck Institute for Intelligent Systems",
-    "version": (2022, 3, 26),
+    "version": (2022, 6, 13),
     "blender": (2, 80, 0),
     "location": "Viewport > Right panel",
     "description": "SMPL-X for Blender",
@@ -445,8 +445,8 @@ class SMPLXSnapGroundPlane(bpy.types.Operator):
 
         obj = bpy.context.object
         if obj.type == 'ARMATURE':
-                    armature = obj
-                    obj = bpy.context.object.children[0]
+            armature = obj
+            obj = bpy.context.object.children[0]
         else:
             armature = obj.parent
 
@@ -893,7 +893,7 @@ class SMPLXLoadPose(bpy.types.Operator, ImportHelper):
 class SMPLXAddAnimation(bpy.types.Operator, ImportHelper):
     bl_idname = "object.smplx_add_animation"
     bl_label = "Add Animation"
-    bl_description = ("Load AMASS (SMPL-X) animation and create animated SMPL-X body")
+    bl_description = ("Load AMASS/SMPL-X animation and create animated SMPL-X body")
     bl_options = {'REGISTER', 'UNDO'}
 
     filter_glob: StringProperty(
@@ -909,6 +909,14 @@ class SMPLXAddAnimation(bpy.types.Operator, ImportHelper):
         ),
     )
 
+    rest_position: EnumProperty(
+        name="Rest position",
+        items=(
+            ("SMPL-X", "SMPL-X", "Use default SMPL-X rest position (feet below the floor)"),
+            ("GROUNDED", "Grounded", "Use feet-on-floor rest position"),
+        ),
+    )
+
     keyframe_corrective_pose_weights: BoolProperty(
         name="Use keyframed corrective pose weights",
         description="Keyframe the weights of the corrective pose shapes for each frame. This increases animation load time and slows down editor real-time playback.",
@@ -981,6 +989,26 @@ class SMPLXAddAnimation(bpy.types.Operator, ImportHelper):
 
         bpy.ops.object.smplx_update_joint_locations('EXEC_DEFAULT')
 
+        height_offset = 0
+        if self.rest_position == "GROUNDED":
+            bpy.ops.object.smplx_snap_ground_plane('EXEC_DEFAULT')
+            height_offset = armature.location[2]
+
+            # Apply location offsets to armature and skinned mesh
+            bpy.context.view_layer.objects.active = armature
+            armature.select_set(True)
+            obj.select_set(True)
+            bpy.ops.object.transform_apply(location = True, rotation=False, scale=False) # apply to selected objects
+            armature.select_set(False)
+
+            # Fix root bone location
+            bpy.ops.object.mode_set(mode='EDIT')
+            bone = armature.data.edit_bones["root"]
+            bone.head = (0.0, 0.0, 0.0)
+            bone.tail = (0.0, 0.0, 0.1)
+            bpy.ops.object.mode_set(mode='OBJECT')
+            bpy.context.view_layer.objects.active = obj
+
         # Keyframe poses
         step_size = int(mocap_framerate / target_framerate)
 
@@ -1007,6 +1035,10 @@ class SMPLXAddAnimation(bpy.types.Operator, ImportHelper):
             for index, bone_name in enumerate(SMPLX_JOINT_NAMES):
                 if bone_name == "pelvis":
                     # Keyframe pelvis location
+
+                    if self.rest_position == "GROUNDED":
+                        current_trans[1] = current_trans[1] - height_offset # SMPL-X local joint coordinates are Y-Up
+
                     armature.pose.bones[bone_name].location = Vector((current_trans[0], current_trans[1], current_trans[2]))
                     armature.pose.bones[bone_name].keyframe_insert('location', frame=current_frame)
 
@@ -1210,7 +1242,8 @@ class SMPLXExportFBX(bpy.types.Operator, ExportHelper):
 
         # Default FBX export settings export all animations. Since we duplicated the armature we have a copy of the animation and the original animation.
         # We avoid export of both by only exporting the active animation for the armature (bake_anim_use_nla_strips=False, bake_anim_use_all_actions=False).
-        bpy.ops.export_scene.fbx(filepath=self.filepath, use_selection=True, apply_scale_options="FBX_SCALE_ALL", add_leaf_bones=False, bake_anim_use_nla_strips=False, bake_anim_use_all_actions=False)
+        # Disable keyframe simplification to ensure that exported FBX animation properly matches up with exported Alembic cache.
+        bpy.ops.export_scene.fbx(filepath=self.filepath, use_selection=True, apply_scale_options="FBX_SCALE_ALL", add_leaf_bones=False, bake_anim_use_nla_strips=False, bake_anim_use_all_actions=False, bake_anim_simplify_factor=0)
 
         print("Exported: " + self.filepath)