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I'm trying to update a script from blender 2.55 to 2.7 which was supposed to work, but here I have an issue, to get the bone matrices I take the armature world_matrix and multiply by the bone local_matrix but all my bone seems to be at 0,0,0. I need to obtain the world matrix of each bone in object mode.

my test code:

import bpy
from bpy.props import *

ob=bpy.context.selected_objects[0]

for bone in ob.modifiers[0].object.pose.bones:
    print("matrix channel",bone.matrix_channel)
for bone in ob.modifiers[0].object.data.bones:
    print("matrix_local",bone.matrix_local)

For both I have 0,0,0 for location (last line 0 0 0 1)

Thanks

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  • $\begingroup$ can you post how you are getting 0,0,0 , and did you try armature.pose.bones[0].matrix_channel $\endgroup$ – Chebhou Mar 14 '15 at 23:32
  • $\begingroup$ A pose bones location is relative to it's rest position, it will be 0,0,0 unless you have moved it in pose mode. $\endgroup$ – sambler Mar 15 '15 at 6:20
  • $\begingroup$ @Chebhou I added the code to my post, I have the same with matrix_channel $\endgroup$ – Entretoize Mar 15 '15 at 9:12
  • $\begingroup$ @sambler I don't find where to get the rest matrix.. $\endgroup$ – Entretoize Mar 15 '15 at 9:52
  • $\begingroup$ OK I finally found the error, it seems that rows and columns have been switched from blender 2.5 to 2.7 or my script was already buggy... Then matrix_local is the one to use. $\endgroup$ – Entretoize Mar 15 '15 at 13:12
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this is not official but after inspection :

  • the last line is not for location in 4*4 matrix

enter image description here

  • matrix_local is the rest matrix in the armature space

  • matrix_channel is the pose matrix according to the rest state

  • i think the last line is there to make a square matrix

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  • 1
    $\begingroup$ FYI the last line is used for non-uniform transformation (IE used in perspective matrix) and is known as the "w" component of the matrix. Should always be (0,0,0,1) unless you want strange things to happen :) $\endgroup$ – beiller Mar 16 '15 at 19:11
  • $\begingroup$ @beiller thanks for the info, feel free to edit and add more $\endgroup$ – Chebhou Mar 16 '15 at 19:20

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