rigging problem / setting local axes

(acidhouse_) #1


One big problem which I have with the skeleton I built is that the axes of the legs and the back are different which caused unwanted behaviour of the feet after the character was skinned. As I am building the bones of the legs downwards and the bones of the back upwards this happens automatically.

In the Blender 2.3 guide I found this comment :
"An easy way to automatically orient the z-axis handles of all selected bones is to press CTRL - N "
If I do this when the armature is in edit mode I get this line “recalc bone roll angles” which is not having an effect on the orientation of the axes.

Here You can have a look at the file with my bone system :


(acidhouse_) #2

my animation professor (who is also teaching blender in his courses)
answered faster than someone from this board so heres the solution…
possibly also interesting for other users who met the same problematic.

  1. Build-up all the bones, as you did before. (Every feet, arm, etc. should
    be a bit bended, and drawed from the proper view.)

  2. Select all these armatures, and with Ctrl J join them into one armature.
    (Or with parent/child connection, as it is necessary.)

  3. Select this armature, go to “Editing” (F9), and then turn on “draw axes”.
    Then you can see the axes of the bones. You will see, that the axes are
    different. Some bones has the Z-axis up, some has the Z-axis to the left,

  4. First you should tell to Blender, that this is the original position of
    your skeleton-model. Please push Ctrl A. This is applying rotation. This
    means, that now all the rotations of the bones will be “0,0,0”, so if you
    push later Alt R (clear rotation), you will get this position. (Please turn
    on numerical menu (N), to see what happens when you make this apply rotation

  5. Select the whole skeleton-model again. Go to edit mode. Then push A, to
    select all the bones. (They should be yellow now.) Then say Ctrl N, and I am
    sure you will see all the axises will be changed to stay on the same way.

  6. That is, your skeleton now is ready to define the IK solvers, and then the
    skinning, and finally the animation.

(sundialsvc4) #3

These two tips are extremely important, as it turns out.

When you assemble an object out of however-many pieces, you naturally rotate them and so-forth to get them into the desired position. So, when you are finished modeling, you have a whole bunch of “parts” which have rotations willy, tilly and non.

At that moment, Blender still remembers where all those objects were “born,” and just how far they’ve been moved and rotated from those original positions. It’s still calculating their present positions by computing the approprite rotation and distance from those original points. It’s still fully prepared, if you instruct it to “clear” the rotation, orientation, and so-forth, to move all those pieces right back where they started!

These steps cause Blender to consider all of these objects, no matter where in space they are now and no matter how they got there, to henceforth be deemed to “right now be in their ‘normal,’ or (0,0,0), position and orientation.” That is, Blender now is ordered to forget about where those objects started in their life, and how far they are now from those original positions, and to consider where they are now right now to be “where they started.” Upon completion of these commands, their displacement from their “original” position and orientation, as Blender now considers it, will be “zero.”