- you know the dimension & location of the box
- you know the dimension & location of player’s capsule
- get player’s extent → find vertices
- if you use this:
You do not even need to inverse the transform since this is world space. If enough points return true, the player is full enveloped.
There may be a better method - that’s just the 1st thing that comes to mind. One way or another, you will need to math it out. Alternatively, consider checking whether the player is close enough to the box centre, taking their extent into account. Could work well enough in some scenarios.