how to cut a mesh?

In my game there are objects which explode on a plane which i call the arena. When they explode I instantiate a place with a “destroyed surface” texture on it just above the arena so it looks like this texture is actually on the arena. The problem is that when an object explodes too close to the edge of the arena the texture just sticks out over the edge. I need to either cut the mesh off at the edge of the arena, or go about this a whole different way. Any suggestions??

There is some ‘Slice’ utility in the Asset Store, but I would suggest:

a) use a roughly circular image, transparent at the corners
b) place the image where the center is no closer than width (and height, assuming square (hence roughly circular)) to the edge
c) place some sort of wall or other barrier around the arena, to cover such slop
d) if your mess needs to be closer to the edge, and the above doesn’t work, you may need to have several versions of the texture, where it’s drawn with transparency to mask off the parts that would hang off the edge. Choose texture appropriately when you place it.