projectVector()

Synopsis

Projects a vector onto a plane, returning a new vector in that plane. The plane is defined by a point and normal vector. The plane normal is the projection direction. If the vector and the normal are aligned, then a degenerate geometry situation is created (a zero vector), but this is not considered an error, since some vector algebra correctly handles zero vectors as intermediate results. Note, however, that handing a zero vector into most geometry-creation functions will cause problems.

Syntax

projectVector ( v As Vector, _
                planePoint As Point, _
                nor As Vector ) As Vector

Argument	Type	Description
v	Vector	The vector to be projected.
planePoint	Point	A point on the projection plane.
nor	Vector	The plane normal vector, and the projection vector.

Example 1

The identity projection.

Intent >projectVector(UnitX, point(0,0,0), UnitZ) 
--> Vector_(1.0, 0.0, 0.0, WorldFrame())

Example 2

Note that this is not an error.

Intent >projectVector(UnitX, point(0,0,0), UnitX) 
--> Vector_(0.0, 0.0, 0.0, WorldFrame()) 

Example 3

X and Y components

 Intent >projectVector(vector(1,1,1), point(0,0,0), vector(0,0,1)) 
--> Vector_(1.0, 1.0, 0.0, WorldFrame())

Example 4

The projectVector() function does not make the projected vector into a unit vector.

 Intent >projectVector(vector(2,2,2), point(0,0,0), vector(1,0,0)) 
--> Vector_(0.0, 2.0, 2.0, WorldFrame())

Example 5

If the plane normal vector is in the same direction as the vector to be projected, the function will return a zero vector.

Intent >projectVector(vector(0,0,1), point(0,0,0), vector(0,0,1)) 
--> Vector_(0.0, 0.0, 0.0, WorldFrame())