contraint item seems to be on a spring

[Adam Trachtenberg]

It sounds like a priority problem. If you’re not familiar with priorities, they basically tell Cinema the order in which different expressions and functions should be evaluated. Generally, if two expressions have the same priority (found in the Basic tab) they will be evaluated from top to bottom in the object manager, or if they’re tags on a single object, from right to left.

In your case I’m guessing that your character is controlled by IK tags with the default (Expression 0) priority, and your constraint tag probably has the same default value. Therefore, if your hair object/constraint tag is above the IK tag in the OM, it will be evaluated before the IK. That’s a problem because you want the constraint tag to know where the IK is *after* it has solved. You may be able to solve the problem by dragging the hair object below the IK structure in the object manager, or if you’ve changed default priorities elsewhere, you’ll have to go through and make sure the constraint tag has a lower priority than the IK tag.

[Bert Brown]

thanks for the response. I never knew what that priority option was. I will try this out, I imagine it is what’s causing the problem

[Adam Trachtenberg]

Yeah, priorities area kind of tricky but they’re very important in complex setups. You can generally tell there’s a problem if you get the delay effect you’re seeing and/or if the scene doesn’t refresh correctly when you rewind the timeline.

I should add to my above post that lower numbers actually mean higher priorities, i.e., Expression -1 will be evaluated before Expression 0.

[Bert Brown]

This actually doesnt seem to be fixing the problem.

I’ve got a “hair object” and a “sunglasses object” that both have a Parent Constraint tag to “Head Control”

They both have an Expression priority at “1” while the Head Control has a PSR at priority “0”

but I’m still getting the problem. any thoughts?