PPF at bottom
BSP Editing
What you need:
-BSP Tools
-Hex Workshop
-Some knowledge about how to edit hex
Getting Started
Well first have 3 copies of your map, for example

OMG I use dothalo, what a nub
Open the original map in glitchy's bsp tools, extract the bsp.
Open (for this example) Coagulation2 in glitchy's bsp tools, flatten map without collision to 0.
Open (for this example) Coagulation3 in glitchy's bsp tools, flatten map with only collision to 0.
Now since you have hex workshop installed, right click coagulation.map and say hex edit in hex workshop, or open hex workshop in some way. Go to tools->compare->Compare Files, and select coagulation, and coagulation2.
Here is where it gets tricky, you know those models you extracted? Well in hex workshop lower right it is gonna have an equal amout of "replaced" thins than the amount of models. The models go in order, so the first replaced is mapmesh0. Second is mapmesh0, so on and so forth. Well since coagulation2 is the one without collision lowered, look at the hex. Every 2 sets of 4 has a float value, which can be found in the lower left. Now go 2 sets of 4 before the red. That float is the x value. After those 2 sets of 4 the next are the y. The final set are the z. It follows this throughout the whole map. So edit the floats as you please.
All I feel like explaining for now, since I know very little about the collision. But with coagulation 3 when you compare it with the original coag you will find where to edit the collision.
Now for the PPF