What would you put to get a trigger to activate at a certain speed or altitude?
I am not sure what exactly you mean. If you want plain speed in whatever direction, I believe there is a separate command for that (
speed, I think) and for altitude you use
getPos whatever select 2.
If you want the total speed as in the magnitude of its total velocity vector using
velocity you would use...
sqrt((velocity thing select 0)*(velocity thing select 0) + (velocity thing select 1)*(velocity thing select 1) + (velocity thing select 2)*(velocity thing select 2))