IK/FK joints with offset parent matrix

[ShinyShadow41]

Hi,

I have made a setup like this and it works fine. But i'm not sure if i should use this setup. Thing that confuses me is: i need to zero out the translations of the bind joints because they already stored in offset parent matrix. Does anyone know if this setup cause problems ?

[Kahylan · Accepted solution]

Hi!

While this setup does work you could run into issues with this, since it doesn't change the BindJoint Translates. Instead this animates the offsets on those joints. Which also leaves you with Bind joints that need to be zeroed out and don't directly reflect the same Translates as their Masters. This isn't optimal but depending on what your rig is for, it might never cause problems.

But it will cause problems in workflows that require animation baking. Because you can't bake the offsetParentMatrix Attribute.

Baking is especially important in Rigs that get animated in Maya and then exported into game engines, because those rigs often get baked and then stripped of everything that isn't the bind skeleton and the skin, and then exported as FBX. This will leave your BindJoints in a static state with no animation as soon as the rest of the setup is deleted.

As long as your Rigs animation never gets baked onto the BindJoints, you should be fine.

[ShinyShadow41]

I understand, thanks.

[Kahylan]

If you don't need the scaling functionality, you can just add decomposeMatrix Nodes after your blendMatrix nodes and feed, outputRotation into rotation and outputTranslation into translation.

Scaling would have to be handled using scale constraints, but most IK/FK setups don't have a scale connection.

[ShinyShadow41]

Yes i will do it like that, i just tried to if i can do this without decomposeMatrix, so there wouldn't be one more extra node.