Hi i want to block animation on one arm if player has flashlight. So i need to add some mask for animation and then apply it with if statement ?
Yes, it is the approach.
You need to use the Avatar Body Mask for this.
The documentation there specifies a case similar to yours only for the use of body masks, which states:
“For example, you may have a standard
walking animation that includes both
arm and leg motion, but if a character
is carrying a large object with both
hands then you wouldn’t want his arms
to swing by his sides as he walks.
However, you could still use the
standard walking animation by
switching off the arm movements in the
body mask.”