Hi All,

I need the simplest way to constrain a null to the surface of a geo. Think of it like the point on a chin… so when the chin moves (eg: is animated), the null follows the chin….

Thanks

firefly9000
Hi All,

I need the simplest way to constrain a null to the surface of a geo. Think of it like the point on a chin… so when the chin moves (eg: is animated), the null follows the chin….

Thanks

The sticky obj node constraints to uv and the rivet to a point group.
I prefer the sticky in most cases.

Thank you - That works for a new Null.

However, if I parent it to a Chain_Goal null of an IK chain all bets are off.

What I'm basically trying to do is have the IK control null follow the point so that it drives the bones attached. I'm watching this tutorial with Simon Payne, but it's for Maya. He basically has blend shapes, but also a rig that moves along with the blend shapes. So let's say you open the mouth via the blendshapes, but then you want just a corner raised, you can use your rig.

But in order for that to work, the rig must follow the blendshapes. My line of thought was to make the Chain_Goal that drives the IK a child of Sticky… or maybe I should pursue another way of doing it?

This all works if I don't capture the geometry. In other words, the null of the IK of the bones syncs to the Sticky and moves with the blendshape. But if I capture the geometry it goes haywire.

I've been able to adapt most of the stuff he says to Houdini but this escapes me.

Thanks again.

Find the InverseKin CHOP that's controlling the bone chain and set its goal to your sticky object instead.

edward
Find the InverseKin CHOP that's controlling the bone chain and set its goal to your sticky object instead.

Did it but it still behaves weirdly. For some reason it moves the Sticky when I do that (see attached). I put some screenshots of parms in case I did something wrong. Thanks

you can be easily creating dependency cycle if you are sticking on geometry deformed by the bone

so make sure your sticky references geometry after blendshapes, but still before Capture/Deform sops

and you will be getting double deformation as moving sticky, therefore ik handle will cause bone to move, and therefore deform, whereas you want it to move and not deform. Deform only when you offset IK from sticky node
to solve that you can update bone's capture pose relative to sticky object
here is example of how to move bone with sticky driven by shape anim and still be able to offset shabe with that bone when you need it
http://www.sidefx.com/index.php?option=com_forum&Itemid=172&page=viewtopic&p=143976#143976 [sidefx.com]

tamte
you can be easily creating dependency cycle if you are sticking on geometry deformed by the bone

so make sure your sticky references geometry after blendshapes, but still before Capture/Deform sops

and you will be getting double deformation as moving sticky, therefore ik handle will cause bone to move, and therefore deform, whereas you want it to move and not deform. Deform only when you offset IK from sticky node
to solve that you can update bone's capture pose relative to sticky object
here is example of how to move bone with sticky driven by shape anim and still be able to offset shabe with that bone when you need it
http://www.sidefx.com/index.php?option=com_forum&Itemid=172&page=viewtopic&p=143976#143976 [sidefx.com]

Yeeeeehaaaaaaa
That worked - Thanks so much Tomas… and I also understand the concept behind it as well. Thanks again… I'm one happy camper now…