cross product

multiplication of vectors

cross product

work in progress...

The cross product or vector product of two vectors in 3D space results in a vector which is perpendicular to both and therefore normal to the plane containing them.

for details on how to calculate the cross product please see 

http://en.wikipedia.org/wiki/Cross_product

to create a procedure for this,

TO CROSSAB :X1 :Y1 :Z1 :X2 :Y2 :Z2
EAST :Y1*:Z2-:Z1*:Y2
UP :Z1*:X2-:X1*:Z2
SOUTH :X1*:Y2-:Y1*:X2
MAKE "C POS
PD
SETPOS :C
PU
END

it may also be useful to show the plane on which the original vectors are found...