rem                            L_PTPL.CDL

rem        Copy Right by International Technology Transfer Corp.
rem        revision 1.0-7/30/99   


rem        Line perpendicular to Plane    



clear
defopt = 2
dspflg = 1

:start
getpos "Indicate Point",defopt

on (@key + 3) goto exit, start, start,
defopt = @key
x0 = @xworld
y0 = @yworld
z0 = @zworld

getplane "Select Plane", dspflg

on (@key + 3) goto exit, start, ,
a = @fltdat[10]
b = @fltdat[11]
c = @fltdat[12]
d = @fltdat[13]

bunbo = sqrt(a * a + b * b + c * c)
f = a / bunbo
g = b / bunbo
h = c / bunbo
x = x0 - f * (a * x0 + b * y0 + c * z0 + d) / bunbo
y = y0 - g * (a * x0 + b * y0 + c * z0 + d) / bunbo
z = z0 - h * (a * x0 + b * y0 + c * z0 + d) / bunbo

line x0, y0, z0, x, y, z
redraw
goto start
:exit