Assuming you're turning the model using turnentity you could try something like this (not tested I'm afraid but should work) ...
You may have to adjust some of the values but make sure the ramp and ground are pickable.
{code}
unused = LinePick ( EntityX(model,True),EntityY(model,True)+10,EntityZ(model,True),0,-20,0,.2 )
y#=PickedY()
TranslateEntity model,0,y-EntityY(model)+.1,0
nx#=PickedNX():ny#=PickedNY():nz#=PickedNZ()
AlignToVector model,nx,ny,nz,2,.25
{code/}
You may have to adjust some of the values but make sure the ramp and ground are pickable.
{code}
unused = LinePick ( EntityX(model,True),EntityY(model,True)+10,EntityZ(model,True),0,-20,0,.2 )
y#=PickedY()
TranslateEntity model,0,y-EntityY(model)+.1,0
nx#=PickedNX():ny#=PickedNY():nz#=PickedNZ()
AlignToVector model,nx,ny,nz,2,.25
{code/}