Specifies how an object z position is determined. See Height Calculation for more information.
For example you may want a tree to rest on a terrain only while a chair you would like to rest on a town
none
Collisions with freeforms are ignored
withprimary
Only a collision with the primary freeform (eg terrain) is a collision
withcollisiondown
Go down until either collide with a freeform (eg town) or the terrain whichever is higher.
withcollisionup
Go up from the terrain till collide with the freeform (eg town) and then keep going till stop colliding. Good to determine ground if town buildings have roofs.
withcollisionupavg
Same as 'withcollisionup' except 3 heights are calculated close together and the smallest is used. Useful to avoid say an object being stuck up on top of a thin column
