Collision Detection and Zones

Td SET ZONE n,zone,x,y,z,r..........defines an invisible spherical zone
around object n where :

n - object number

zone - zone number

x,y,z - position of zone centre

r - radius of sphere

=Td ZONE Z(n,z)..........returns the Z co-ordinate of the zones centre in
world co-ordinates.  Here z is a zone on object n

=Td ZONE R(n,z)..........returns the radius of zone z on object n

Td DELETE ZONE n,zn......If zn>0, removes zone zn from object n, otherwise
all collision zones are removed from the object