io_anim_bvh/import_bvh.py

   1 # SPDX-License-Identifier: GPL-2.0-or-later
   2
   3 # Script copyright (C) Campbell Barton
   4
   5 from math import radians, ceil
   6
   7 import bpy
   8 from mathutils import Vector, Euler, Matrix
   9
  10
  11 class BVH_Node:
  12     __slots__ = (
  13         # Bvh joint name.
  14         'name',
  15         # BVH_Node type or None for no parent.
  16         'parent',
  17         # A list of children of this type..
  18         'children',
  19         # Worldspace rest location for the head of this node.
  20         'rest_head_world',
  21         # Localspace rest location for the head of this node.
  22         'rest_head_local',
  23         # Worldspace rest location for the tail of this node.
  24         'rest_tail_world',
  25         # Worldspace rest location for the tail of this node.
  26         'rest_tail_local',
  27         # List of 6 ints, -1 for an unused channel,
  28         # otherwise an index for the BVH motion data lines,
  29         # loc triple then rot triple.
  30         'channels',
  31         # A triple of indices as to the order rotation is applied.
  32         # [0,1,2] is x/y/z - [None, None, None] if no rotation..
  33         'rot_order',
  34         # Same as above but a string 'XYZ' format..
  35         'rot_order_str',
  36         # A list one tuple's one for each frame: (locx, locy, locz, rotx, roty, rotz),
  37         # euler rotation ALWAYS stored xyz order, even when native used.
  38         'anim_data',
  39         # Convenience function, bool, same as: (channels[0] != -1 or channels[1] != -1 or channels[2] != -1).
  40         'has_loc',
  41         # Convenience function, bool, same as: (channels[3] != -1 or channels[4] != -1 or channels[5] != -1).
  42         'has_rot',
  43         # Index from the file, not strictly needed but nice to maintain order.
  44         'index',
  45         # Use this for whatever you want.
  46         'temp',
  47     )
  48
  49     _eul_order_lookup = {
  50         (None, None, None): 'XYZ',  # XXX Dummy one, no rotation anyway!
  51         (0, 1, 2): 'XYZ',
  52         (0, 2, 1): 'XZY',
  53         (1, 0, 2): 'YXZ',
  54         (1, 2, 0): 'YZX',
  55         (2, 0, 1): 'ZXY',
  56         (2, 1, 0): 'ZYX',
  57     }
  58
  59     def __init__(self, name, rest_head_world, rest_head_local, parent, channels, rot_order, index):
  60         self.name = name
  61         self.rest_head_world = rest_head_world
  62         self.rest_head_local = rest_head_local
  63         self.rest_tail_world = None
  64         self.rest_tail_local = None
  65         self.parent = parent
  66         self.channels = channels
  67         self.rot_order = tuple(rot_order)
  68         self.rot_order_str = BVH_Node._eul_order_lookup[self.rot_order]
  69         self.index = index
  70
  71         # convenience functions
  72         self.has_loc = channels[0] != -1 or channels[1] != -1 or channels[2] != -1
  73         self.has_rot = channels[3] != -1 or channels[4] != -1 or channels[5] != -1
  74
  75         self.children = []
  76
  77         # List of 6 length tuples: (lx, ly, lz, rx, ry, rz)
  78         # even if the channels aren't used they will just be zero.
  79         self.anim_data = [(0, 0, 0, 0, 0, 0)]
  80
  81     def __repr__(self):
  82         return (
  83             "BVH name: '%s', rest_loc:(%.3f,%.3f,%.3f), rest_tail:(%.3f,%.3f,%.3f)" % (
  84                 self.name,
  85                 *self.rest_head_world,
  86                 *self.rest_head_world,
  87             )
  88         )
  89
  90
  91 def sorted_nodes(bvh_nodes):
  92     bvh_nodes_list = list(bvh_nodes.values())
  93     bvh_nodes_list.sort(key=lambda bvh_node: bvh_node.index)
  94     return bvh_nodes_list
  95
  96
  97 def read_bvh(context, file_path, rotate_mode='XYZ', global_scale=1.0):
  98     # File loading stuff
  99     # Open the file for importing
 100     file = open(file_path, 'rU')
 101
 102     # Separate into a list of lists, each line a list of words.
 103     file_lines = file.readlines()
 104     # Non standard carrage returns?
 105     if len(file_lines) == 1:
 106         file_lines = file_lines[0].split('\r')
 107
 108     # Split by whitespace.
 109     file_lines = [ll for ll in [l.split() for l in file_lines] if ll]
 110
 111     # Create hierarchy as empties
 112     if file_lines[0][0].lower() == 'hierarchy':
 113         # print 'Importing the BVH Hierarchy for:', file_path
 114         pass
 115     else:
 116         raise Exception("This is not a BVH file")
 117
 118     bvh_nodes = {None: None}
 119     bvh_nodes_serial = [None]
 120     bvh_frame_count = None
 121     bvh_frame_time = None
 122
 123     channelIndex = -1
 124
 125     lineIdx = 0  # An index for the file.
 126     while lineIdx < len(file_lines) - 1:
 127         if file_lines[lineIdx][0].lower() in {'root', 'joint'}:
 128
 129             # Join spaces into 1 word with underscores joining it.
 130             if len(file_lines[lineIdx]) > 2:
 131                 file_lines[lineIdx][1] = '_'.join(file_lines[lineIdx][1:])
 132                 file_lines[lineIdx] = file_lines[lineIdx][:2]
 133
 134             # MAY NEED TO SUPPORT MULTIPLE ROOTS HERE! Still unsure weather multiple roots are possible?
 135
 136             # Make sure the names are unique - Object names will match joint names exactly and both will be unique.
 137             name = file_lines[lineIdx][1]
 138
 139             # print '%snode: %s, parent: %s' % (len(bvh_nodes_serial) * '  ', name,  bvh_nodes_serial[-1])
 140
 141             lineIdx += 2  # Increment to the next line (Offset)
 142             rest_head_local = global_scale * Vector((
 143                 float(file_lines[lineIdx][1]),
 144                 float(file_lines[lineIdx][2]),
 145                 float(file_lines[lineIdx][3]),
 146             ))
 147             lineIdx += 1  # Increment to the next line (Channels)
 148
 149             # newChannel[Xposition, Yposition, Zposition, Xrotation, Yrotation, Zrotation]
 150             # newChannel references indices to the motiondata,
 151             # if not assigned then -1 refers to the last value that will be added on loading at a value of zero, this is appended
 152             # We'll add a zero value onto the end of the MotionDATA so this always refers to a value.
 153             my_channel = [-1, -1, -1, -1, -1, -1]
 154             my_rot_order = [None, None, None]
 155             rot_count = 0
 156             for channel in file_lines[lineIdx][2:]:
 157                 channel = channel.lower()
 158                 channelIndex += 1  # So the index points to the right channel
 159                 if channel == 'xposition':
 160                     my_channel[0] = channelIndex
 161                 elif channel == 'yposition':
 162                     my_channel[1] = channelIndex
 163                 elif channel == 'zposition':
 164                     my_channel[2] = channelIndex
 165
 166                 elif channel == 'xrotation':
 167                     my_channel[3] = channelIndex
 168                     my_rot_order[rot_count] = 0
 169                     rot_count += 1
 170                 elif channel == 'yrotation':
 171                     my_channel[4] = channelIndex
 172                     my_rot_order[rot_count] = 1
 173                     rot_count += 1
 174                 elif channel == 'zrotation':
 175                     my_channel[5] = channelIndex
 176                     my_rot_order[rot_count] = 2
 177                     rot_count += 1
 178
 179             channels = file_lines[lineIdx][2:]
 180
 181             my_parent = bvh_nodes_serial[-1]  # account for none
 182
 183             # Apply the parents offset accumulatively
 184             if my_parent is None:
 185                 rest_head_world = Vector(rest_head_local)
 186             else:
 187                 rest_head_world = my_parent.rest_head_world + rest_head_local
 188
 189             bvh_node = bvh_nodes[name] = BVH_Node(
 190                 name,
 191                 rest_head_world,
 192                 rest_head_local,
 193                 my_parent,
 194                 my_channel,
 195                 my_rot_order,
 196                 len(bvh_nodes) - 1,
 197             )
 198
 199             # If we have another child then we can call ourselves a parent, else
 200             bvh_nodes_serial.append(bvh_node)
 201
 202         # Account for an end node.
 203         # There is sometimes a name after 'End Site' but we will ignore it.
 204         if file_lines[lineIdx][0].lower() == 'end' and file_lines[lineIdx][1].lower() == 'site':
 205             # Increment to the next line (Offset)
 206             lineIdx += 2
 207             rest_tail = global_scale * Vector((
 208                 float(file_lines[lineIdx][1]),
 209                 float(file_lines[lineIdx][2]),
 210                 float(file_lines[lineIdx][3]),
 211             ))
 212
 213             bvh_nodes_serial[-1].rest_tail_world = bvh_nodes_serial[-1].rest_head_world + rest_tail
 214             bvh_nodes_serial[-1].rest_tail_local = bvh_nodes_serial[-1].rest_head_local + rest_tail
 215
 216             # Just so we can remove the parents in a uniform way,
 217             # the end has kids so this is a placeholder.
 218             bvh_nodes_serial.append(None)
 219
 220         if len(file_lines[lineIdx]) == 1 and file_lines[lineIdx][0] == '}':  # == ['}']
 221             bvh_nodes_serial.pop()  # Remove the last item
 222
 223         # End of the hierarchy. Begin the animation section of the file with
 224         # the following header.
 225         #  MOTION
 226         #  Frames: n
 227         #  Frame Time: dt
 228         if len(file_lines[lineIdx]) == 1 and file_lines[lineIdx][0].lower() == 'motion':
 229             lineIdx += 1  # Read frame count.
 230             if (
 231                     len(file_lines[lineIdx]) == 2 and
 232                     file_lines[lineIdx][0].lower() == 'frames:'
 233             ):
 234                 bvh_frame_count = int(file_lines[lineIdx][1])
 235
 236             lineIdx += 1  # Read frame rate.
 237             if (
 238                     len(file_lines[lineIdx]) == 3 and
 239                     file_lines[lineIdx][0].lower() == 'frame' and
 240                     file_lines[lineIdx][1].lower() == 'time:'
 241             ):
 242                 bvh_frame_time = float(file_lines[lineIdx][2])
 243
 244             lineIdx += 1  # Set the cursor to the first frame
 245
 246             break
 247
 248         lineIdx += 1
 249
 250     # Remove the None value used for easy parent reference
 251     del bvh_nodes[None]
 252     # Don't use anymore
 253     del bvh_nodes_serial
 254
 255     # importing world with any order but nicer to maintain order
 256     # second life expects it, which isn't to spec.
 257     bvh_nodes_list = sorted_nodes(bvh_nodes)
 258
 259     while lineIdx < len(file_lines):
 260         line = file_lines[lineIdx]
 261         for bvh_node in bvh_nodes_list:
 262             # for bvh_node in bvh_nodes_serial:
 263             lx = ly = lz = rx = ry = rz = 0.0
 264             channels = bvh_node.channels
 265             anim_data = bvh_node.anim_data
 266             if channels[0] != -1:
 267                 lx = global_scale * float(line[channels[0]])
 268
 269             if channels[1] != -1:
 270                 ly = global_scale * float(line[channels[1]])
 271
 272             if channels[2] != -1:
 273                 lz = global_scale * float(line[channels[2]])
 274
 275             if channels[3] != -1 or channels[4] != -1 or channels[5] != -1:
 276
 277                 rx = radians(float(line[channels[3]]))
 278                 ry = radians(float(line[channels[4]]))
 279                 rz = radians(float(line[channels[5]]))
 280
 281             # Done importing motion data #
 282             anim_data.append((lx, ly, lz, rx, ry, rz))
 283         lineIdx += 1
 284
 285     # Assign children
 286     for bvh_node in bvh_nodes_list:
 287         bvh_node_parent = bvh_node.parent
 288         if bvh_node_parent:
 289             bvh_node_parent.children.append(bvh_node)
 290
 291     # Now set the tip of each bvh_node
 292     for bvh_node in bvh_nodes_list:
 293
 294         if not bvh_node.rest_tail_world:
 295             if len(bvh_node.children) == 0:
 296                 # could just fail here, but rare BVH files have childless nodes
 297                 bvh_node.rest_tail_world = Vector(bvh_node.rest_head_world)
 298                 bvh_node.rest_tail_local = Vector(bvh_node.rest_head_local)
 299             elif len(bvh_node.children) == 1:
 300                 bvh_node.rest_tail_world = Vector(bvh_node.children[0].rest_head_world)
 301                 bvh_node.rest_tail_local = bvh_node.rest_head_local + bvh_node.children[0].rest_head_local
 302             else:
 303                 # allow this, see above
 304                 # if not bvh_node.children:
 305                 #     raise Exception("bvh node has no end and no children. bad file")
 306
 307                 # Removed temp for now
 308                 rest_tail_world = Vector((0.0, 0.0, 0.0))
 309                 rest_tail_local = Vector((0.0, 0.0, 0.0))
 310                 for bvh_node_child in bvh_node.children:
 311                     rest_tail_world += bvh_node_child.rest_head_world
 312                     rest_tail_local += bvh_node_child.rest_head_local
 313
 314                 bvh_node.rest_tail_world = rest_tail_world * (1.0 / len(bvh_node.children))
 315                 bvh_node.rest_tail_local = rest_tail_local * (1.0 / len(bvh_node.children))
 316
 317         # Make sure tail isn't the same location as the head.
 318         if (bvh_node.rest_tail_local - bvh_node.rest_head_local).length <= 0.001 * global_scale:
 319             print("\tzero length node found:", bvh_node.name)
 320             bvh_node.rest_tail_local.y = bvh_node.rest_tail_local.y + global_scale / 10
 321             bvh_node.rest_tail_world.y = bvh_node.rest_tail_world.y + global_scale / 10
 322
 323     return bvh_nodes, bvh_frame_time, bvh_frame_count
 324
 325
 326 def bvh_node_dict2objects(context, bvh_name, bvh_nodes, rotate_mode='NATIVE', frame_start=1, IMPORT_LOOP=False):
 327
 328     if frame_start < 1:
 329         frame_start = 1
 330
 331     scene = context.scene
 332     for obj in scene.objects:
 333         obj.select_set(False)
 334
 335     objects = []
 336
 337     def add_ob(name):
 338         obj = bpy.data.objects.new(name, None)
 339         context.collection.objects.link(obj)
 340         objects.append(obj)
 341         obj.select_set(True)
 342
 343         # nicer drawing.
 344         obj.empty_display_type = 'CUBE'
 345         obj.empty_display_size = 0.1
 346
 347         return obj
 348
 349     # Add objects
 350     for name, bvh_node in bvh_nodes.items():
 351         bvh_node.temp = add_ob(name)
 352         bvh_node.temp.rotation_mode = bvh_node.rot_order_str[::-1]
 353
 354     # Parent the objects
 355     for bvh_node in bvh_nodes.values():
 356         for bvh_node_child in bvh_node.children:
 357             bvh_node_child.temp.parent = bvh_node.temp
 358
 359     # Offset
 360     for bvh_node in bvh_nodes.values():
 361         # Make relative to parents offset
 362         bvh_node.temp.location = bvh_node.rest_head_local
 363
 364     # Add tail objects
 365     for name, bvh_node in bvh_nodes.items():
 366         if not bvh_node.children:
 367             ob_end = add_ob(name + '_end')
 368             ob_end.parent = bvh_node.temp
 369             ob_end.location = bvh_node.rest_tail_world - bvh_node.rest_head_world
 370
 371     for name, bvh_node in bvh_nodes.items():
 372         obj = bvh_node.temp
 373
 374         for frame_current in range(len(bvh_node.anim_data)):
 375
 376             lx, ly, lz, rx, ry, rz = bvh_node.anim_data[frame_current]
 377
 378             if bvh_node.has_loc:
 379                 obj.delta_location = Vector((lx, ly, lz)) - bvh_node.rest_head_world
 380                 obj.keyframe_insert("delta_location", index=-1, frame=frame_start + frame_current)
 381
 382             if bvh_node.has_rot:
 383                 obj.delta_rotation_euler = rx, ry, rz
 384                 obj.keyframe_insert("delta_rotation_euler", index=-1, frame=frame_start + frame_current)
 385
 386     return objects
 387
 388
 389 def bvh_node_dict2armature(
 390         context,
 391         bvh_name,
 392         bvh_nodes,
 393         bvh_frame_time,
 394         rotate_mode='XYZ',
 395         frame_start=1,
 396         IMPORT_LOOP=False,
 397         global_matrix=None,
 398         use_fps_scale=False,
 399 ):
 400
 401     if frame_start < 1:
 402         frame_start = 1
 403
 404     # Add the new armature,
 405     scene = context.scene
 406     for obj in scene.objects:
 407         obj.select_set(False)
 408
 409     arm_data = bpy.data.armatures.new(bvh_name)
 410     arm_ob = bpy.data.objects.new(bvh_name, arm_data)
 411
 412     context.collection.objects.link(arm_ob)
 413
 414     arm_ob.select_set(True)
 415     context.view_layer.objects.active = arm_ob
 416
 417     bpy.ops.object.mode_set(mode='OBJECT', toggle=False)
 418     bpy.ops.object.mode_set(mode='EDIT', toggle=False)
 419
 420     bvh_nodes_list = sorted_nodes(bvh_nodes)
 421
 422     # Get the average bone length for zero length bones, we may not use this.
 423     average_bone_length = 0.0
 424     nonzero_count = 0
 425     for bvh_node in bvh_nodes_list:
 426         l = (bvh_node.rest_head_local - bvh_node.rest_tail_local).length
 427         if l:
 428             average_bone_length += l
 429             nonzero_count += 1
 430
 431     # Very rare cases all bones could be zero length???
 432     if not average_bone_length:
 433         average_bone_length = 0.1
 434     else:
 435         # Normal operation
 436         average_bone_length = average_bone_length / nonzero_count
 437
 438     # XXX, annoying, remove bone.
 439     while arm_data.edit_bones:
 440         arm_ob.edit_bones.remove(arm_data.edit_bones[-1])
 441
 442     ZERO_AREA_BONES = []
 443     for bvh_node in bvh_nodes_list:
 444
 445         # New editbone
 446         bone = bvh_node.temp = arm_data.edit_bones.new(bvh_node.name)
 447
 448         bone.head = bvh_node.rest_head_world
 449         bone.tail = bvh_node.rest_tail_world
 450
 451         # Zero Length Bones! (an exceptional case)
 452         if (bone.head - bone.tail).length < 0.001:
 453             print("\tzero length bone found:", bone.name)
 454             if bvh_node.parent:
 455                 ofs = bvh_node.parent.rest_head_local - bvh_node.parent.rest_tail_local
 456                 if ofs.length:  # is our parent zero length also?? unlikely
 457                     bone.tail = bone.tail - ofs
 458                 else:
 459                     bone.tail.y = bone.tail.y + average_bone_length
 460             else:
 461                 bone.tail.y = bone.tail.y + average_bone_length
 462
 463             ZERO_AREA_BONES.append(bone.name)
 464
 465     for bvh_node in bvh_nodes_list:
 466         if bvh_node.parent:
 467             # bvh_node.temp is the Editbone
 468
 469             # Set the bone parent
 470             bvh_node.temp.parent = bvh_node.parent.temp
 471
 472             # Set the connection state
 473             if(
 474                     (not bvh_node.has_loc) and
 475                     (bvh_node.parent.temp.name not in ZERO_AREA_BONES) and
 476                     (bvh_node.parent.rest_tail_local == bvh_node.rest_head_local)
 477             ):
 478                 bvh_node.temp.use_connect = True
 479
 480     # Replace the editbone with the editbone name,
 481     # to avoid memory errors accessing the editbone outside editmode
 482     for bvh_node in bvh_nodes_list:
 483         bvh_node.temp = bvh_node.temp.name
 484
 485     # Now Apply the animation to the armature
 486
 487     # Get armature animation data
 488     bpy.ops.object.mode_set(mode='OBJECT', toggle=False)
 489
 490     pose = arm_ob.pose
 491     pose_bones = pose.bones
 492
 493     if rotate_mode == 'NATIVE':
 494         for bvh_node in bvh_nodes_list:
 495             bone_name = bvh_node.temp  # may not be the same name as the bvh_node, could have been shortened.
 496             pose_bone = pose_bones[bone_name]
 497             pose_bone.rotation_mode = bvh_node.rot_order_str
 498
 499     elif rotate_mode != 'QUATERNION':
 500         for pose_bone in pose_bones:
 501             pose_bone.rotation_mode = rotate_mode
 502     else:
 503         # Quats default
 504         pass
 505
 506     context.view_layer.update()
 507
 508     arm_ob.animation_data_create()
 509     action = bpy.data.actions.new(name=bvh_name)
 510     arm_ob.animation_data.action = action
 511
 512     # Replace the bvh_node.temp (currently an editbone)
 513     # With a tuple  (pose_bone, armature_bone, bone_rest_matrix, bone_rest_matrix_inv)
 514     num_frame = 0
 515     for bvh_node in bvh_nodes_list:
 516         bone_name = bvh_node.temp  # may not be the same name as the bvh_node, could have been shortened.
 517         pose_bone = pose_bones[bone_name]
 518         rest_bone = arm_data.bones[bone_name]
 519         bone_rest_matrix = rest_bone.matrix_local.to_3x3()
 520
 521         bone_rest_matrix_inv = Matrix(bone_rest_matrix)
 522         bone_rest_matrix_inv.invert()
 523
 524         bone_rest_matrix_inv.resize_4x4()
 525         bone_rest_matrix.resize_4x4()
 526         bvh_node.temp = (pose_bone, bone, bone_rest_matrix, bone_rest_matrix_inv)
 527
 528         if 0 == num_frame:
 529             num_frame = len(bvh_node.anim_data)
 530
 531     # Choose to skip some frames at the beginning. Frame 0 is the rest pose
 532     # used internally by this importer. Frame 1, by convention, is also often
 533     # the rest pose of the skeleton exported by the motion capture system.
 534     skip_frame = 1
 535     if num_frame > skip_frame:
 536         num_frame = num_frame - skip_frame
 537
 538     # Create a shared time axis for all animation curves.
 539     time = [float(frame_start)] * num_frame
 540     if use_fps_scale:
 541         dt = scene.render.fps * bvh_frame_time
 542         for frame_i in range(1, num_frame):
 543             time[frame_i] += float(frame_i) * dt
 544     else:
 545         for frame_i in range(1, num_frame):
 546             time[frame_i] += float(frame_i)
 547
 548     # print("bvh_frame_time = %f, dt = %f, num_frame = %d"
 549     #      % (bvh_frame_time, dt, num_frame]))
 550
 551     for i, bvh_node in enumerate(bvh_nodes_list):
 552         pose_bone, bone, bone_rest_matrix, bone_rest_matrix_inv = bvh_node.temp
 553
 554         if bvh_node.has_loc:
 555             # Not sure if there is a way to query this or access it in the
 556             # PoseBone structure.
 557             data_path = 'pose.bones["%s"].location' % pose_bone.name
 558
 559             location = [(0.0, 0.0, 0.0)] * num_frame
 560             for frame_i in range(num_frame):
 561                 bvh_loc = bvh_node.anim_data[frame_i + skip_frame][:3]
 562
 563                 bone_translate_matrix = Matrix.Translation(
 564                     Vector(bvh_loc) - bvh_node.rest_head_local)
 565                 location[frame_i] = (bone_rest_matrix_inv @
 566                                      bone_translate_matrix).to_translation()
 567
 568             # For each location x, y, z.
 569             for axis_i in range(3):
 570                 curve = action.fcurves.new(data_path=data_path, index=axis_i, action_group=bvh_node.name)
 571                 keyframe_points = curve.keyframe_points
 572                 keyframe_points.add(num_frame)
 573
 574                 for frame_i in range(num_frame):
 575                     keyframe_points[frame_i].co = (
 576                         time[frame_i],
 577                         location[frame_i][axis_i],
 578                     )
 579
 580         if bvh_node.has_rot:
 581             data_path = None
 582             rotate = None
 583
 584             if 'QUATERNION' == rotate_mode:
 585                 rotate = [(1.0, 0.0, 0.0, 0.0)] * num_frame
 586                 data_path = ('pose.bones["%s"].rotation_quaternion'
 587                              % pose_bone.name)
 588             else:
 589                 rotate = [(0.0, 0.0, 0.0)] * num_frame
 590                 data_path = ('pose.bones["%s"].rotation_euler' %
 591                              pose_bone.name)
 592
 593             prev_euler = Euler((0.0, 0.0, 0.0))
 594             for frame_i in range(num_frame):
 595                 bvh_rot = bvh_node.anim_data[frame_i + skip_frame][3:]
 596
 597                 # apply rotation order and convert to XYZ
 598                 # note that the rot_order_str is reversed.
 599                 euler = Euler(bvh_rot, bvh_node.rot_order_str[::-1])
 600                 bone_rotation_matrix = euler.to_matrix().to_4x4()
 601                 bone_rotation_matrix = (
 602                     bone_rest_matrix_inv @
 603                     bone_rotation_matrix @
 604                     bone_rest_matrix
 605                 )
 606
 607                 if len(rotate[frame_i]) == 4:
 608                     rotate[frame_i] = bone_rotation_matrix.to_quaternion()
 609                 else:
 610                     rotate[frame_i] = bone_rotation_matrix.to_euler(
 611                         pose_bone.rotation_mode, prev_euler)
 612                     prev_euler = rotate[frame_i]
 613
 614             # For each euler angle x, y, z (or quaternion w, x, y, z).
 615             for axis_i in range(len(rotate[0])):
 616                 curve = action.fcurves.new(data_path=data_path, index=axis_i, action_group=bvh_node.name)
 617                 keyframe_points = curve.keyframe_points
 618                 keyframe_points.add(num_frame)
 619
 620                 for frame_i in range(num_frame):
 621                     keyframe_points[frame_i].co = (
 622                         time[frame_i],
 623                         rotate[frame_i][axis_i],
 624                     )
 625
 626     for cu in action.fcurves:
 627         if IMPORT_LOOP:
 628             pass  # 2.5 doenst have cyclic now?
 629
 630         for bez in cu.keyframe_points:
 631             bez.interpolation = 'LINEAR'
 632
 633     # finally apply matrix
 634     arm_ob.matrix_world = global_matrix
 635     bpy.ops.object.transform_apply(location=False, rotation=True, scale=False)
 636
 637     return arm_ob
 638
 639
 640 def load(
 641         context,
 642         filepath,
 643         *,
 644         target='ARMATURE',
 645         rotate_mode='NATIVE',
 646         global_scale=1.0,
 647         use_cyclic=False,
 648         frame_start=1,
 649         global_matrix=None,
 650         use_fps_scale=False,
 651         update_scene_fps=False,
 652         update_scene_duration=False,
 653         report=print,
 654 ):
 655     import time
 656     t1 = time.time()
 657     print("\tparsing bvh %r..." % filepath, end="")
 658
 659     bvh_nodes, bvh_frame_time, bvh_frame_count = read_bvh(
 660         context, filepath,
 661         rotate_mode=rotate_mode,
 662         global_scale=global_scale,
 663     )
 664
 665     print("%.4f" % (time.time() - t1))
 666
 667     scene = context.scene
 668     frame_orig = scene.frame_current
 669
 670     # Broken BVH handling: guess frame rate when it is not contained in the file.
 671     if bvh_frame_time is None:
 672         report(
 673             {'WARNING'},
 674             "The BVH file does not contain frame duration in its MOTION "
 675             "section, assuming the BVH and Blender scene have the same "
 676             "frame rate"
 677         )
 678         bvh_frame_time = scene.render.fps_base / scene.render.fps
 679         # No need to scale the frame rate, as they're equal now anyway.
 680         use_fps_scale = False
 681
 682     if update_scene_fps:
 683         _update_scene_fps(context, report, bvh_frame_time)
 684
 685         # Now that we have a 1-to-1 mapping of Blender frames and BVH frames, there is no need
 686         # to scale the FPS any more. It's even better not to, to prevent roundoff errors.
 687         use_fps_scale = False
 688
 689     if update_scene_duration:
 690         _update_scene_duration(context, report, bvh_frame_count, bvh_frame_time, frame_start, use_fps_scale)
 691
 692     t1 = time.time()
 693     print("\timporting to blender...", end="")
 694
 695     bvh_name = bpy.path.display_name_from_filepath(filepath)
 696
 697     if target == 'ARMATURE':
 698         bvh_node_dict2armature(
 699             context, bvh_name, bvh_nodes, bvh_frame_time,
 700             rotate_mode=rotate_mode,
 701             frame_start=frame_start,
 702             IMPORT_LOOP=use_cyclic,
 703             global_matrix=global_matrix,
 704             use_fps_scale=use_fps_scale,
 705         )
 706
 707     elif target == 'OBJECT':
 708         bvh_node_dict2objects(
 709             context, bvh_name, bvh_nodes,
 710             rotate_mode=rotate_mode,
 711             frame_start=frame_start,
 712             IMPORT_LOOP=use_cyclic,
 713             # global_matrix=global_matrix,  # TODO
 714         )
 715
 716     else:
 717         report({'ERROR'}, "Invalid target %r (must be 'ARMATURE' or 'OBJECT')" % target)
 718         return {'CANCELLED'}
 719
 720     print('Done in %.4f\n' % (time.time() - t1))
 721
 722     context.scene.frame_set(frame_orig)
 723
 724     return {'FINISHED'}
 725
 726
 727 def _update_scene_fps(context, report, bvh_frame_time):
 728     """Update the scene's FPS settings from the BVH, but only if the BVH contains enough info."""
 729
 730     # Broken BVH handling: prevent division by zero.
 731     if bvh_frame_time == 0.0:
 732         report(
 733             {'WARNING'},
 734             "Unable to update scene frame rate, as the BVH file "
 735             "contains a zero frame duration in its MOTION section",
 736         )
 737         return
 738
 739     scene = context.scene
 740     scene_fps = scene.render.fps / scene.render.fps_base
 741     new_fps = 1.0 / bvh_frame_time
 742
 743     if scene.render.fps != new_fps or scene.render.fps_base != 1.0:
 744         print("\tupdating scene FPS (was %f) to BVH FPS (%f)" % (scene_fps, new_fps))
 745     scene.render.fps = new_fps
 746     scene.render.fps_base = 1.0
 747
 748
 749 def _update_scene_duration(
 750         context, report, bvh_frame_count, bvh_frame_time, frame_start,
 751         use_fps_scale):
 752     """Extend the scene's duration so that the BVH file fits in its entirety."""
 753
 754     if bvh_frame_count is None:
 755         report(
 756             {'WARNING'},
 757             "Unable to extend the scene duration, as the BVH file does not "
 758             "contain the number of frames in its MOTION section",
 759         )
 760         return
 761
 762     # Not likely, but it can happen when a BVH is just used to store an armature.
 763     if bvh_frame_count == 0:
 764         return
 765
 766     if use_fps_scale:
 767         scene_fps = context.scene.render.fps / context.scene.render.fps_base
 768         scaled_frame_count = int(ceil(bvh_frame_count * bvh_frame_time * scene_fps))
 769         bvh_last_frame = frame_start + scaled_frame_count
 770     else:
 771         bvh_last_frame = frame_start + bvh_frame_count
 772
 773     # Only extend the scene, never shorten it.
 774     if context.scene.frame_end < bvh_last_frame:
 775         context.scene.frame_end = bvh_last_frame