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This hasn't been solved. Is there something wrong with the Avatar Mask?

This doesn't change much, since I was already parenting the weapon to the Camera quite easily with the Transform Action. Nonetheless, I appreciate the fact that you're working on this.

I would like to clarify my problem to make it easier for you: The arms and gun are animated by an animator. So they have to be in the same instance. They also need to be the Player model, in order to use States and Gestures. The Muzzle also has to be of the same instance, or it won't follow the animation of the gun. But the problem is that the Muzzle must be instantiated. It cannot exist in the same instance as the Player.

A solution for now is to have the arms, gun, and Muzzle all be a prefab and be instantiated by the Draw Action. Then, as you told me, use a custom animator on the Muzzle to animate the whole instance. But this is very cumbersome and hacky I feel. I have experimented with it and come to the conclusion that it requires way too much effort to make things feel half decent.

This was resolved in Discord. The solution is to put a custom Animator Controller in the Animator field of the Muzzle component. Then use Triggers to call those animations.

Yep, Wait 0 seconds works as well (thanks @kingofzombies)

4) Headshots should cause more damage.

That's what I had. Is this wrong??

Docs said to use IK_leftFoot and IK_rightFoot. I tried your spelling and the docs'. Doesn't work.

Error is gone.

However, my method above doesn't actually work:
The Muzzle does not follow the animation of the Player (I used Character Model Action to change arms, then parented Muzzle to the arms). I think the Muzzle and the arms have to be one instance. So what I think we need is the ability to change the Player Model to a prefab that contains both the animator and Muzzle.

Nope. Using 2018.4.11f1.

There are games using an Adventure Camera where when you shoot from ease state, you shoot in the direction camera is facing. So it would work if you have the "where you want to shoot" on the Shooting state as well.

Aside from that, if you Aim Weapon right away after drawing, how would that work for snipers? There'd be no way to do 360* no scopes (lol). And you know in Call of Duty and Battlefield, they have "steady breathing" which would probably be an additional state. I could think of a bunch of examples but another one would be when an enemy comes around the corner it's much better to hip-fire rather than aiming down sights then shooting, especially for shotguns.

There are just too many restrictions.