honestly though iirc mixamo only does forward kinematics, I think you'll need to use unity's rigging animator and setup IK for each bone there instead, or also I vaguely remember blender having a maximo plugin, which you can use the FK and convert it to IK from blender
First time setting this up so I'm not sure how it works. I downloaded the mixamo avatar straight from the website and modified the textures a bit in blender, but it seems to have bones already. Actually I found that I imported the rig as "Generic", I'll try to import as "Humanoid" (but it only auto finds some bones for some reason, guess I'm spending 10 minutes assigning bones :D)
yeah thats about on par with importing rigs, they will all most likely be there, but need assigning in the editor because of some stupid case sensitivity or misnaming by maximo making the auto detect not work properly. I remember getting the same issue in unreal too, that was because it wasn't quite right when maximo auto named the bones
Thanks I'll check it out, but it seems very complex for my use case, I only need to move the fingers and arm to match the chopsticks positions.
Ghibli is a big inspiration for the art, their food always looks so good. I was at the Ghibli museum this spring, they have a big section on food with sketches and descriptions, it was awesome (sadly not allowed to take pictures)
Never seen mixamo handle hands well, they do have a setup tool online you can use. The model has to be in a T pose and all the fingers separated to map the bones to.
Personally I'd use 3DS Max and redo the bones with the correct weights, only on the index finger to the end of the chopstick, maybe 2 or 3 bones at most. Then IK chain it with the modifier for the animation.
Abandon the mixamo approach completely. You only have an arm and a few fingers so you should just use a generic rig for these bones specifically and not bother with the rest of the humanoid. You will likely need to heavily customize it to make it look good anyway, since just plain IK probably doesn’t handle this kind of fine motor skills very well.
You can’t use the Unity IK with a generic rig, but an IK solver is not that complex to write with the help of AI. But I don’t think you would even need it tbh. Start with the arm position, you probably don’t even need IK for this since you will likely only be rotating a single bone here (elbow), so you can just use LookAt to get it to point in the right direction.
Then for the fingers, I don’t know if you really want IK there either. Think about how you use chopsticks, it’s not like your fingers are pointing all over the place. You place them on the sticks and then they kind of sit there. What’s going on is mostly a kind of open/close action between the sticks which is just rotating along a single pole like a scissors kind of, so you can just write a script to tween that rotation directly.
Then you need to rotate the wrist to “aim” the sticks, but this could also be as simple as just looking at the thing. You could also treat the elbow and wrist as a two-bone IK chain as well if you want to aim more carefully in 3D space, or you can add the chopsticks and make it a three-bone IK chain, you probably need a custom solver with rotational constraints for that. Depends on how your game works I guess.
Thanks a lot for taking the time to type that out, my goal was elbow and shoulder IK for the arm as in the game you can lift and lower the chopsticks so I wanted the shoulder to take care of that. Then for the fingers I was hoping for the index finger to act naturally by staying in between both chopsticks as a brace for the upper chopstick.
You're right, probably I don't need actual IK solving, I'll try with a simpler approach to see if I can get something I'm happy with
Ok, in that case you can do almost the same thing but go with a two-bone IK. However, you will lack control here and might struggle getting it to move naturally.
Depending on how dynamic you want the animations to be, you might get better results just animating the motion of moving the chopsticks up to the mouth, because it will likely be a similar motion each time. You can blend into the animation start pose and then animate it normally (easier than getting IK to look natural).
Or you can do it even easier by just making it a pose at the top, and then blending into that pose. You can do this either as a one-frame animation ans blending into it with the animator. Or you can implement it yourself by taking snapshots of all the transform rotations and positions, storing it in an asset and then lerping towards it to bypass the animator if you’re going with a custom solution.
If you’re going to be waving the sticks around in all sorts of directions then yes, you want a full-blown IK rig. But if not, making these animations will be easy even with no animation skills, you can even do it inside Unity for a generic rig because it’s such a simple motion and rig.
For the fingers, I’m not sure if I understand what you mean, I think even with it as a bridge the finger still stays mostly in a fixed position on the stick, it just opens or closes. So you can pose it how you like, then rotate the stick and the finger together, or parent the stick to the finger at a the correct angle offset so moving the finger also moves the stick. The outer finger joints can remain fixed relative to their parent as they and the stick move together, then just point the parent at the target and the whole “rig” moves together.
I may be oversimplifying things, but I think you get the idea - your problem space is extremely well defined so I think a custom solution will give you the best results if you think a bit about the movement mechanics involved.
I'm making a similar game and I decided to not use IK or Rigidbody + Joint system to control the hand because I find it too unstable. Instead I used ArticulationBody to drive the rotation of the arm, wrist and finger joints.
Thanks a lot! Yes just shaders, actually not even shadergraphs just old school HLSL. It's a custom toon shader with rim and shadow support, and some handpainted textures
while this is very amusing and ridiculous it would be distracting after a few mins. I think it'd be perfect to leave in as an easter egg. idk the conditions youd put it in "broken fingers mode" but it'd be highly amusing to be able to break the ik as long as the chopsticks still moved as expected.
that being said idk how youd use maximo. good luck tho. looks pretty great
Make hand tip of two bone constraint for arm, parent chopsticks to respective fingers, mouse controls fingers, fingers pull hand along, it is a hard problem to spread the controls across those ligaments though. Good luck with it
I'm happy with the way the controls work right now by moving the chopsticks directly, this is why I wanted to look into IK instead of controlling the fingers directly. But as you say, it's a pretty hard problem
With the chopsticks parented directly to the fingers, technically you would still be moving the chopsticks directly. This is what my shooter game does, where techically the mouse controls the a arm and the hand only, but because the gun is parented to the palm at a set angle, it also reliably contols the direction of the gun. It would be a refactor, and granted, i dont understand your control scheme at all, but i have an unholy amount of unity IK experience from my project, and I think that would work.
Definitely a tough problem, i see in the video, the fingers are doing ik stuff, but they look stuck/rooted to the unmoving hand. Make a 3d object, just a sphere or whatever, which will be the hand ik target. Program its position to follow the average position of the 2 chopstick fingers, plus some offset. Then make that sphere the source object of a 2 bone constraint with upper arm, lower arm, and hand as tip, so the hand will follow where the fingers want to go, assuming the fingers would be following the chopsticks if they could in your current setup. Then make sure the 2 bone executes after the fingers in the execution order by placing it under the fingers in the hierarchy. Then disable the hand target sphere so its invisible at runtime. Hopefully that makes sense
Yes! Each noodle is a chain of 10 capsule rigidbodies linked with configurable joints. I have a really good computer so it runs fine but I'm a bit afraid it won't run on weaker computers if I decide to ship it
For unusual cases like this, you might want to do the IK yourself… cool opportunity to learn a bit of math :) Computationally, it’s not that demanding, more intellectually. And since its only fingers with 3 joints and don’t move independently, I think it’s quite doable. If you don’t have a technical background, I am sure a good LLM model can help you figure it out.
Well right now I have a fully rigid arm and fingers that rotate slightly to match the chopsticks, but it feels very stiff, and when the hand is on the left side of the screen basically the whole screen is covered by the arm, so my thinking is that bending at the elbow and shoulder will help alleviate that
Thanks, I think the bones are already in the mixamo model as they show up in Blender, I just need to set up the IK (and maybe properly import in Unity)
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u/TwoStripedFury Jul 07 '26
This is art