The materia2l property sets the splash damage ID of a an object.
This ID is used when objects collide with each other such as projeciles.
Material2 is used within the projectiles radius with a falloff.
Example:
In this example the material is 216, this refers to a material defined in the
damage_system folder in the game.rfa. Each material defines how much damge it
does to other materials.
If you see material2, this refers to splash damage.
Material is direct damage.