rem                            ANG_2PL.CDL

rem       Copy Right by International Technology Transfer Corp.    


rem        Angle between 2 planes

rem        1. Select 2 planes
rem        2. Show the intersection angle
rem        revision 1.0-7/30/99



clear
dspflg = 1

:start
getplane "Select First Method To Set Plane", dspflg

on (@key + 3) goto exit, start,
a1 = @fltdat[10]
b1 = @fltdat[11]
c1 = @fltdat[12]
d1 = @fltdat[13]

getplane "Select Second Method To Set Plane", dspflg

on (@key + 3) goto exit, start, 
a2 = @fltdat[10]
b2 = @fltdat[11]
c2 = @fltdat[12]
d2 = @fltdat[13]

bunbo = sqrt((a1 * a1 + b1 * b1 + c1 * c1) * (a2 * a2 + b2 * b2 + c2 * c2))
naiseki = a1 * a2 + b1 * b2 + c1 * c2

theta = acos( naiseki / bunbo )
if (theta>90)
	theta = 180 - theta

pause "Angle between Two planes = %.5f ", theta
redraw
goto start
:exit