It's simple enough...

What annoys me is the object limit. But it seems rather buggy even with 12 objects I've made 5 enviroment mods and 2 of them crashes after a while, 1 had wall that didnt work ingame (just little cube instead the wall...) the cause is probally that those two mods have objects "stucked" on the wall from where you can climb, crashing is still pretty random...