View Full Version : How do you Bake the Root bone?

07 July 2007, 11:29 PM
I'm having a problem with a rig. My root bone was rigged to have a group parent above it that has a point and orient constraint on it. The object driving the constraints was a Nurbs cube. Pretty standard setup, right?
I can bake Simulation and get curves generated for every Joint in my skeleton EXCEPT the root bone. The root bone just gets static curves.
The curves get placed onto the Group above my root.

It seems like it would work if you could get the group node to just pass the data to the root bone, without accepting any values itself.
Has anybody else had this problem before? If so, how to work around it? My goal is an animated model without any transforms in the skeleton at all.


07 July 2007, 04:35 AM
Well, your root bone has to have transforms on it if you don't want the group node, otherwise it will just simply not move around. The reason why all your other bones bake is because they are driven from the parent movement which travels all the way up to your group node. It's pretty common for the root node to receive the brunt of transforms in a games rig, however I'd suggest keeping it to the topmost group if possible. If not, bake the group nodes, unparent the root, parent constrain the root to the group node, bake the root node and let it inherit the transforms from the group, delete the constraint afterwards and toss the group if you want.


07 July 2007, 04:49 PM
Thanks so much for your input! I had never used the Parent constraint, and it would definately solve the issue. I will need to keep the group parent because it scales up my skeleton.
I had the 'aha!' moment when I realized that the group was baking because it was the one being constrained. The root was merely following it. So I needed to apply the constraint one node down. I solved the problem by:
deleting the original constraints on the group, and constraining the root joint to the NURBS box control directly.
The orient constraint makes the bone absorb the rotation offsets that the group used to absorb, and it goes all wonky. So I checked the Joint Orient values on the root bone. The values here sometimes can be put directly into the offset values, but they can also be the difference between that value and 90 degrees. These offsets set the bone back to its right orientation. The Root bakes now!

Thanks for the advice, Shawn.

07 July 2007, 07:21 PM
Congrats man :) Baking and constraints are always finicky things and I know our animation team here despises having to work with the 'techy stuff' a great deal.

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07 July 2007, 07:21 PM
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