The game I am currently working on involves many pieces that come towards the player. Assuming that these pieces are all the same, for example a rock model, would it be more effective to combine them using the combine mesh script, or leave them as they are? Each rock on the screen is currently creating one draw call, and I am trying to figure out how to cut that down so that I can have more rocks on the screen at once.
No it should be combine theml automatically if sharing the same material.
Check out your build settings.