Question 2D IK - Bone chain involved in animations + script based Solver target movement = erratic

Hello!

Unity 2020.2.1 (which is awesome, great work!)
Newest versions of Unity 2D Animation packages w/ the IK built-in.

So, we have a typical human rig, including wrist/hand bones.




The solvers for the arms are CCD chain in the hand, using a chain of 4 to get back up to the shoulder / upper arm:




Like the title suggests, the Solver "target" is being moved in a Script (for aiming a weapon), as well as in some animations. When control is fully isolated (script only, or animations only), movement is fluid, perfect.
When both are active during gameplay, we get some frantic motion. Initially, this was solved by moving the logic in the script so that instead of only updating solver.target on player input, to constantly setting position in Update() [yuck]. It seems however, the more animation states that I add which utilize the arms in some way, the more this conflict over "who has control" grows, and there's always a slight jitter of position/rotation happening -- even when those Animation states are not playing or being transitioned to/from.

I realize my approach might be entirely crazy to begin with, but I had hoped that the Animator would "back off" so to speak - leave the limbs alone when they're not needed in a current Animation state.

Just for full picture sake, this is how the solver.target is being moved in script:

Code (CSharp):

1. // rightHand is a Solver2D
2. // newPos is a Vector3.
3. rightHand.GetChain(0).target.transform.localPosition = newPos;

I feel like there is a setting I'm missing, or another weird thought I had and I've found nothing online about this type of question:

• Can I use 2 Solvers on the same limb chain?
  
  • One with a Solver.weight of say 0.5f, used in Animations to move solver.target
  • The other used in script, with Solver.weight = 1f (So that if the script is trying to move it, it takes priority).

Would that work, or make things even more erratic?

Thanks, Unity rocks my socks, keep up the great work!

 

The multiple solvers is a no-go. The last in control of an effector just takes over.

Then there is toggling solvers.enabled back & forth, I guess that's the solution?

 

Hi Ted, wow what a great response!

First off, I did wind up at a solution. It involved multiple solvers, and toggling them on/off in script.

I previously tried everything you mentioned, except I didn't specifically set the Script solver to not Solve From Default Pose while leaving that setting enabled for the animation solver. I will test that out of curiosity.

I'm very interested on 2 things you did to get yours to work that way:

• What Animator.updateMode did you set (normal/physics)
• When did you update solver.target position in script [ Update(), LateUpdate(), input polling, etc ]?

Thanks for such a thoughtful response! I don't see a way to mark this thread as "solved" but if there is, it definitely can be.

 

Okay, your method worked perfectly as well. I think I had something slightly off the first time I tried it, perhaps the 2 solvers shared a target, which now I understand why that would not work.