Foot Placement IK

I am trying to switch from Mecanim's built-in IK to the Animation Rigging package.

My foot placement IK system is dependent on raycasting from the FK position of each foot before any IK is applied. Getting the FK position is straight forward with Mecanim's built-in IK, but it seems like I need to create an animation job to get the same result with Animation Rigging?

If I go through the trouble of learning how to create that animation job I'm still not sure I will be able to raycast from within the animation job to get the information I need. The presentations on YouTube and the examples in GitHub all seem to avoid any physics based input.

I would appreciate some guidance! This is a common use of IK and I'm sure others would benefit from an example implementation.

 

This is what is preventing me from using the animation rigging package as much as I want to. Because we cannot perform raycasts after animation, foot IK will always lag one frame behind without using some form of messy extrapolation.

 

You can do it modifying original script and binding vector3 position in job. Just try to understand their scripts.

 

Hello. I've encountered the same problem as you mentioned. Do you have a solution on how to get the FK postion to do the raycast?

 

I think DebugLogError's point is how to get the FK position of the bone where we do the raycasting. With Mecanim's built-in IK we can get the value by animator.GetBoneTransform() in OnAnimatorIK(), but when using Animation Rigging，not only in Update but also in LateUpdate, the bone position is the position after rigging.

 

Did anyone ever find a solution to this? Seems like foot placement based off raycast from FK would be a common use case (and unfortunately not having it being a major stopgap to using Animation Rigging at all).

 

Jebtor has already stated it's not possible to raycast from the FK position using animation rigging due to the multithreaded nature of jobs.

The best you can do is raycast inside update before the animator has run and feed this value into your jobs. It will lag, but it might not look that bad. If your game runs at 60fps I doubt anyone is going to notice a single frame lag on your feet ik

Or if you really want perfection do your foot IK placement inside LateUpdate instead, after animation rigging has run. You'll be back on the main thread though so may aswell stick to standard IK at that point.

 

I too would like to do this.

Has anyone experimented with using the timing of the Playable graph and running the graph twice per frame? Like this:

• Disable the IK nodes in the Playable graph and run. (only the animation runs)
• Do the raycasting. The rig should be in the pure animated pose with no IK applied.
• Disable the animation node in the tree and enable the IK nodes
• Run the graph again. Now only the IK nodes should run.

Is there a downside to this? It would be clearly less efficient but how slow would it be? Is there a reason this wouldn't work?

 

I just got around and experimented with the animation rigging package. It's really powerful and nice ! I was also under the impression that I could go about and rig a character a bit like a full body IK, but it turns out to be impossible since the system is made to be a sort of override/make animation from scratch using unity animations. For a character that you already rigged in a 3D software it kind of defeat the purpose by re-rigging it again, then rig the controller for it. I mean I've done it yesterday and it's really cool to have a rig inside unity, but I would never do a prod animating characters inside unity it goes against my pipeline habit.

What I ended up doing today tho realizing this limitations is : Make an Hybrid character from Final IK and Constraining the various target so that the motion would be really clean and automated when my programmer goes on to lerp the desired target positions. That way I was able to fix the twist bones (it's so nice to finally have something that works in that regards) in a rig layer, then added the arm controller motions and Center of mass motion to damp it a bit more. And most importantly Final IK handles the Foot replacement IK + is additive to the underlying animation.

All in all it's a really neat way of doing secondary motion, or if you dare to animate a character inside unity there's at least a way to do it now , but otherwise I would much keep it as simple as it can get and keep this for fully procedural animations.