Loading...
> >

Rigging question: Helper bones

colcurvecolcurve Posts: 162
in The Commons

Hi, one question

I have two bones, rigging a plane (half plane foreach bone, soft weight gradient in between).

Now I want a third bone, basically in the middle of the two halfs, influencing a small area, for "independent" finetuning.

When I paint weight for this last bone, it modifies the weigts of the other bones due to weight normalization.

But this has the effect, that when posing the two first bones, the mesh curve is no longer soft, but has anomalies near the area of influence of the last bone.

What is the best strategy to rig helper bones, that shall logically be applied last, so that they do not interfere with the main bones?

Thanks :)

 

Comments

  • Richard HaseltineRichard Haseltine Posts: 102,813

    What is the hierarchy here?

  • colcurvecolcurve Posts: 162

    See here, the two bones with gradient weight for smooth bending, and in the geometry editor, selected the place for finetuning with an extra bone. I do not want to make a morph because tweaking bones are more flexible

    rig_example.jpg
    1282 x 611 - 124K
  • colcurvecolcurve Posts: 162

    now, when using the helper bone as last child in the hierarchy, the weight paint will normalize with the second bone, so that the weight painted to helper bone will not distort second bone if the helper bone is not posed. but despite helper bone not posed, it will distort bone 1

    rig_helper_bone_full_weight.jpg
    1080 x 673 - 129K
  • colcurvecolcurve Posts: 162

    what i want is that helper bone modifies both bone 1 and 2, but only when helper bone is actually used.... not when it is zeroed.... you get the idea?

  • Richard HaseltineRichard Haseltine Posts: 102,813

    What are the weights once you have the helper bone set up? Does it have to be at the end of the hierarchy chain?

  • colcurvecolcurve Posts: 162

    i set the helper bone weights all to 1.0

    and i believe, this automatically includes the helper bone weights into the weights of bone #2, because all child node weights are automatically included

    I do not insist in maintaing the bone at the end of the hierarchy, but I cannot find any other working place for it....

    if I move it between bone 1 and bone 2, then rotating the helper bone will also rotate bone2 which I do not want.

     

    maybe I need to make a helper1 and helper2 bone and use helper1 for bone1 and helper2 for bone2, but thats a bit clumsy... I have lots of usecases for such bones....

     

  • Richard HaseltineRichard Haseltine Posts: 102,813

    As ytou say, when you move bone 2 then the weights of all its child bones are also applied (otherwise they'd be left behind when posing). I've been thinking about this and I'm not sure there is a way to handle it - you either get unwanted bending or you lose the position of the bone (if you move it to the top of the hierarchy and stop normalising weights)..

  • colcurvecolcurve Posts: 162

    I think the weight of grandchild bones must not be greater than the weight of the child bone at any place, otherwise it will "overbend".

    It seems the tools cannot automatically hold this invariant.

Sign In or Register to comment.