Ok, some maths again:

the projected point P_ on the plane is:

P_ = B_ + r * ( D_ - B_ )

with

r = ( n_ dot (A_ - B_) ) / ( n_ dot (D_ - B_) )

n_ is the normal vector of the plane, A_ is a point on the plane.

if n_ dot (D_-B_) = 0, the intersecting ray is parallel to the plane and
does not intersect.

See also
http://geometryalgorithms.com/Archive/algorithm_0105/algorithm_0105.htm#Segm
ent-Plane

Max

-----Original Message-----
From: A. Murat Tanyer [mailto:[EMAIL PROTECTED]]
Sent: Friday, 5 April 2002 22:23
To: [EMAIL PROTECTED]
Subject: [JAVA3D] projections


Hi;

I want to find the projection of a point3D (a point on a shape3D which
is 'B' in the figure) on to the plane ('AF' in the figure) which is
defined by a normal vector and a point on it (not the perpendicular
projection; but through the line of DB). Does anybody have an idea?

BCDE is the surface of a Shape3D object and AF is the plane which
intersect the object.

Thanks in advance.

Regards
Murat




A*
     *
B......*......................C
  .........*...................
  .............*...............
  ................*............
  ...................*.........
D......................*......E
                           *
                              *F

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