Why are my avatar hands not closed when performing clap animation downloaded from mixamo

Question

I am using finalIk to rig my avatar in my project. Looks okay. I also have a few animations downloaded from mixamo that I am using with it. However, there is a particular animation (clapping) that when used on my avatar, the two hands do not meet with each other. for some avatars, the hands go into each other, the clapping are not proper like it is shown in mixamo.

Edit: I have noticed that I can solve this with the Character Arm-Space variable (see attached image) in mixamo's animation options. How can I control this variable at run time.

Answer 1

Problems like that are pretty common when trying to retarget animations from one character to another. The reason why it occurs is probably that the positions and lengths of the arm bones of your character don't exactly match those of the character the animation was designed for. So when the same bone rotations are applied, the hand-bone ends up in a slightly different position.

One possible solution can be to use inverse cinematics. When you set the IK position for both hands to the same position, then you can "glue" the hands to a specific point in 3d space.

Now if you enable IK permanently, then the hands will of course not clap but stick together. That's probably not what you want in this case. You only want them to meet during a certain point of the clapping animation. This can be achieved by also animating their IK weights. So you can only give the hands an IK weight when close to the contact phase of the clapping animation, and let the animation control the hands during the rest of the animation.