void nvp2pl_c ( ConstSpiceDouble normal[3],
ConstSpiceDouble point [3],
SpicePlane * plane )
Make a CSPICE plane from a normal vector and a point.
PLANES
GEOMETRY
MATH
PLANE
Variable I/O Description
  
normal,
point I A normal vector and a point defining a plane.
plane O A CSPICE plane structure representing the plane.
normal,
point
are, respectively, a normal vector and point that
define a plane in threedimensional space. normal
need not be a unit vector. Let the symbol < a, b >
indicate the inner product of vectors a and b;
then the geometric plane is the set of vectors x
in threedimensional space that satisfy
< x  point, normal > = 0.
plane is a CSPICE plane structure that represents the
geometric plane defined by point and normal.
None.
1) If the input vector normal is the zero vector, the error
SPICE(ZEROVECTOR) is signaled.
None.
CSPICE geometry routines that deal with planes use the `plane'
data type to represent input and output planes. This data type
makes the subroutine interfaces simpler and more uniform.
The CSPICE routines that produce CSPICE planes from data that
define a plane are:
nvc2pl_c ( Normal vector and constant to plane )
nvp2pl_c ( Normal vector and point to plane )
psv2pl_c ( Point and spanning vectors to plane )
The CSPICE routines that convert CSPICE planes to data that
define a plane are:
pl2nvc_c ( Plane to normal vector and constant )
pl2nvp_c ( Plane to normal vector and point )
pl2psv_c ( Plane to point and spanning vectors )
Any of these last three routines may be used to convert this
routine's output, plane, to another representation of a
geometric plane.
1) Project a vector v orthogonally onto a plane defined by point
and normal. proj is the projection we want; it is the
closest vector in the plane to v.
nvp2pl_c ( normal, point, &plane );
vprjp_c ( v, &plane, proj );
2) Given a point in a plane and a normal vector, find the
distance of the plane from the origin. We make a
`plane' from the point and normal, then convert the
plane to a unit normal and constant. The output constant
is (according to the specification of pl2nvc_c) the distance of
the plane from the origin.
nvp2pl_c ( normal, point, &plane );
pl2nvc_c ( &plane, normal, constant );
None.
[1] `Calculus and Analytic Geometry', Thomas and Finney.
N.J. Bachman (JPL)
CSPICE Version 1.0.0, 05MAR1999 (NJB)
normal vector and point to plane
