Some code for using your mouse to deform terrain. It is written for Blitz, but some of the code could probably be used for AT. Using "-","+" to change brush radius and "{","}" to change rate of deform. You'll get the idea as to how it works. Enjoy.
sw#=screen width():sh#=screen height()
radius# = BT GetTerrainSize(g_TerrainID)/50
rate# = 1
do
if keystate(13) then radius#=(radius#+0.05)
if keystate(12) and radius#>0 then radius#=(radius#-0.05)
if keystate(27) then rate#=(rate#+0.005)
if keystate(26) and rate#>0 then rate#=(rate#-0.005)
crx#=camera angle x()+mousemovey()/4.0
cry#=camera angle y()+mousemovex()/4.0
rotate camera crx#,cry#,0
if rightkey() then move camera right 1
if leftkey() then move camera left 1
if upkey() then move camera 1
if downkey() then move camera -1
mc = 0
if mouseclick()=1
repeat
move camera 1
inc mc
cx# = camera position x()
cz# = camera position z()
h# = BT GetGroundHeight(g_TerrainID,cx#,cz#)
maxc = (2*BT GetTerrainSize(g_TerrainID))
until (camera position y() < h#) or mc > maxc
BT RaiseTerrain g_TerrainID,cx#,cz#,radius#,rate#
move camera -mc
endif
if mouseclick()=2
repeat
move camera 1
inc mc
cx# = camera position x()
cz# = camera position z()
h# = BT GetGroundHeight(g_TerrainID,cx#,cz#)
maxc = (2*BT GetTerrainSize(g_TerrainID))
until (camera position y() < h#) or mc > maxc
BT RaiseTerrain g_TerrainID,cx#,cz#,radius#,-rate#
move camera -mc
endif
position mouse sw#/2,sh#/2
set cursor 0,0
print "ground height: "+ str$(h#,1)
print "brush radius: " + str$(radius#,1)
print "deform rate: " + str$(rate#,1)
sync
loop
