Mixing Unity Mecanim and Scripted Bones/States

Questions & Answers
1

The problem is that when the Animator component is enabled, it stops any bone movement/rotation in script. Even if you mask out the area where the bone you want to modify is, the animator still impedes.

Version: Unity 4.3.1f1

I noticed that if I enable Animate Physics on the Animator component that I am able to edit the bone rotations but the pose seems to skew the movement on the ground but I think this is because it runs Mecanim in FixedUpdate().

Modifying the bone in the LateUpdate() loop works but if down the line I need something to run after, then I would be almost out of luck. Is this still the only means of working around this issue?

Update 2014-1-20: I just stumbled upon the Optimize Game Objects option under the rig section of your model. This is a great feature to save memory and probably CPU but there is NO way to mix script bones with Mecanim when you enable this feature. Even when you use the Expose Transform option, modifying those transforms has absolutely no effect. I assume this is because it is mainly thought of as a read-only type of nodes to attach to or spawn things.

Previous Update: I just noticed the following quote from this article:

“Update 5 Dec 2013: Today I noticed that Unity 4.3 has added the Animator.Update() which could be used to implement the ragdoll to animation blend more elegantly without the LateUpdate() trickery. I’ll have to update this example when I have time.”

I do not see Animator.Update() in the script reference and I am not sure how to hook/use this loop. Is this new function the way to go and how can it be used?

Edit: It seems that since Animator.Update() is not a virtual method that you can not override it and they made Animator a sealed type which prevents inheritance (so you can’t hide and extend the method).

The main question of this section is: How do I mix Mecanim with scripts for some of the bones?

I know there is a Animator.SetLookAtPosition (and Animator.SetLookAtWeight) methods but rather than an IK type look method, I have a head look script (which you can see in this question) that responds to the mouse.

I can think of a workaround where I make a blend tree with parameter for head rotation that blends left, right, up, down head animations and then adjust the parameter in the head look script. But this seems like a lot of work for simple stuff and might be a problem with the transition time (lagging behind mouse).

I really like the Mecanim system to use the IK system for holding a weapon and the blending of animations but if there are no proper setups then what kind of best alternatives are there?

Possible Alternatives (haven’t used):

IK:

Animation Blending/Transitioning:

  • I can’t find any

Here are some other links talking about this issue:

2

Yes you are correct about “Animate Physics” checkbox - it simply makes Mecanim update in sync with the physics timestep instead of the game’s framerate, so adjusting bones in LateUpdate when using “Animate Physics” will give weird unpredictable syncing problems depending on the framerate the project is running at.

As you’ve found, you can modify the bones successfully in LateUpdate() when Animate Physics is unchecked, and if you need further scripts to be executed after these particular LateUpdate scripts, you can use Unity’s Script Execution Order controls to ensure other scripts with LateUpdate functions occur afterwards.

Animator.Update() allows you to manually update the animator according to whatever timestep you pass. This is useful when you want control over the ‘deltaTime’ that the animator is using rather than letting it play back according to the current timeScale.

You can use this for timescale-independent animation. Here’s an example of an explosion and physics playing with the timescale set to 0.03, so it’s super-slow motion, and I’m manually calling Animator.Update(t) on the controller for the landing gear of the aeroplane, where ‘t’ is calculated using Time.realtimeSinceStartup so the wheels are extending and retracting at a normal speed, within the slow-motion scene.

Slightly weird demo, I know - but I happened to have this project open at the time a few days ago when someone else asked about Animator.Update() :slight_smile: