Player decal and performance

I’m thinking of applying a decal ring at the base of players, and I’m wondering about its performance as if like to have it paint the ring even if the player is really high in the air and what affect having such a large z axis box value would cause. Or would there a better way to keep a smaller projecting always on the ground below a player.

Also in the same aspect what about applying a decal to a players back like a jersey number. Any large permanent hit there?

You can always set ring decal location from hit result by doing trace below the character using blueprints. As for back decal you can add spine bone socket and add decal component to it, but it is not preffered way because projection doesn’t align with animation(decal will slide), so probably better way is to blend numbers texture within mesh material.