Here I attached a test terrain model entity. It has cartesian numbering on the ground level, to measure the sound effect.
The curious thing about the terrains I have done, is that they emit sound near the center axis of the model (the central point, up to number two, if the parameter collision mode is zero.
This seems to be related to the collision ellipse or sphere, but at this time I don't know how to make it larger, to be as large as the terrain model.
I placed many comments on the fpe, if anyone want to experiment and post its results.
If parameter "defaultstatic" is not present on the fpe, when walking over the terrain it emits sound, only if there is a segment on the same layer, painted on the same space of the terrain.
If anyone can find the solution, post it here.
May the 3d force B with U