chain-flipping after constraining

[MacF]

hey there.

although their rotation values are set at zero, it might be safer to simply match their local rotation axis. or more specifically, match the rotation axis of your control object to your joint chain. you can do this by creating a null group, orient constraining it to the joint's rotation axis, deleting the contraint, and parenting your control object under the null group. freeze the transformations on your control group also to reapply the new local axis the null has given it.

this is a leg/arm chain right? are you using an IK solver on the chain? and what kind of constraint are you using? bit more info might help someone else here solve it for you! :thumbsup:

[Darksuit]

Stopping the Flip on constraints.

Orient Constraint -- dont use! (bad bad bad) -- this controls the internal Rotations Axis. You want to control the Visible Rotational Axis. Oreint Constraint is used to multiple objects not single object control.

Parent Constaint Rotate Only -- This is a much cleaner way to control the rotation on an object.


What I think you are actually talking about is the fact that you are execpting the control to rotate in a given direction and it is rotating oposite to what you expect. While yes adding a Mull to offset the rotation does work. It is a bit of a hack. Whats occuring is that you have a control or bone that is in the negative axis, and you are attempting to control it with Positive values. The purpose of the Null or is to offset the controls so that it obtains a negative value that is the same as the joint.

I take it that you are doing a FK setup. As with IK this is rarely an issue. You can also solve this issue by using a multiply/divide node to invert the values of the control you are using.

[MrMint]

Thank you very much for your input guys.
I would have overlooked the negative-axis driven by positive values-issue (added to my internal checklist). Pretty obvious when you hear it but I am sure I would never have figured it out by myself.
I just do it like the did on the gnomon puppet-rig where the instructor grouped the control twice. One group as extra sdk-group and above an offset-group. I always parented the groups to the joint, zeroed out the rotation and translation and unparented it afterwards.It worked twice without any problem.

Not sure what I did different but letting mel do this tedious task this time.
And yes, its an FK-Control for the shoulder. I didnt thought about that this would be important, thats why I just told how the axis are aligned. (also added to my checklist *cough* ).

These just drives me mad. I will take a look why it comes out differently this time.

I thank you both very much again.

Cheers. :beer:

[CGTalk Moderation]

This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.