[Sidefx-houdini-list] Forward Kinematics in Houdini

Pablo Giménez pablogipi at gmail.com
Sun May 2 13:08:42 EDT 2010


Another point relatad with bones is orientation.
In Maya, joints has a kind of local tranformation, so you can change the
joint orientation without changing the rest of the chain, I think is called
Joint orientation.
How can I achieve the same effect with houdini bones.
Lets say I have a leg bones chain, and I want to orient the first bone so
the positive X rotation will move it forward, but after drawing the whole
chain my "forward" rotation is using -X. If I then rotate the bone in the Z
axis 180 deegres then I got thje proper rotation for the first bone but it
affect the rest of the chain reversing all the children bones.
So what is the best way to change bones rotation locally, not affecting the
rest  of the chain so I can choose what axis is going to drive the rotation
i need for evry bone movement?
Hope the example is clear enough.
thanks

2010/4/30 Edward Lam <edward at sidefx.com>

> Pablo Giménez wrote:
> >> The bone object has a "Kinematic Solver" parameter that indicates the
> >> path to the InverseKin CHOP to use for its rotations when computing its
> >> local transform. By doing so, this frees the Bone's regular rotation
> >> parameter for FK keyframe animation.
> >>
> > Makes sense.
> > So the blend parameter controls when the bone will use the rotations from
> > CHOP  or from its own rotations, isn't it?
>
> Effectively, yes. When the Kinematic Solver parameter is specified, the
> Bone will always cook with values from the CHOP. The InverseKin CHOP
> will blend between the bone's FK rotations with its own solved rotations.
>
> -Edward
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-- 
Un saludo
Best Regards
Pablo Giménez



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