If you use an Auto Rig (or the Toon Character), and you pose the character's legs and adjust the Leg Twist effector, then rotate the character via the Character Placer's Rotate Y parameter, the both R & L Leg Twist effectors position gets altered as you rotate it. Is this to be expected? Is there a work around?

How to reproduce:

1) Place a Toon character in a blank scene

2) Pull the R Leg's ankle back in Z and hte L Leg's ankle foward.

3) Adjust the R & L leg twist effectors accordingly

4) Change to a Top view in the scene viewer

5) Change the Character Placer's Rotate Y param.

The Right leg effector seems to move. That or I'm hallucinating.

Houdini version 10.0.595 64 bit, Windows Vista 64.

That's how I would expect it to behave. The Character Placer is the root of the entire rig hierarchy. Anything you do to it will affect everything else in the rig.

Also, the leg controls by default exist in the rigs transform space, so you get that effect. However, with the legs and arms you can change the control space. If you modify the Custom Space blend sliders you can transfer the IK of the legs/arms to another transform space. By default, the object path is empty so at full blend the ankles for example will default to object space and move so their (0,0,0) transform is at the origin. If you then twist the Character Placer they remain still.

That's how I would expect it to behave.

Really? Then why would only one of the effectors change? Both have been altered, but when the character is rotated only one changes, and the resulting change *distorts* the original pose you put your character in a way that you're not expecting.

The problem is that everything is seems to be affected by the transform in a uniform manner, i.e. when the placer is rotated, all the rest of the rig follows along with it as I would expect. The twist effectors are *not* doing that for some reason.

Here's some more detail on what I'm referring to, in case there's some confusion:

1st position:



After rotating clock wise:


Note that the right effector has maintained its position relative to the placer. The left one has move on it's own during the rotation. That can't be normal behavior. The result is that the left knee is altered and moves forward.

Sorry about that. I didn't tweak things around enough to make it noticeable. The problem you are getting is a result of the fact that the leg twist controls don't inherit rotations from the parent body part. If you look inside the leg at the blend_ik_leg_twist_space