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