How to calculate the length of a vector at the point of intersection with a plane
Calculate the length of a vector, from the origin to the intersection with a plane.  | We require: - a point P on the plane
- the normal n of the plane
- the intersecting vector v from the origin
| We will now calculate d, which is the length of vector v needed for it to intersect the plane. | d = | ( nx × Px ) + ( ny × Py ) + ( nz × Pz ) | | ( nx × vx ) + ( ny × vy ) + ( nz × vz ) | If the vector v was a unit vector (of length 1) then the length d is in units. If the vector v was not a unit vector, then: - if 0<d<1 then the vector intersects the plane within its length
- if d>1 then the vector intersects the plane after its length
- if d<0 then the vector intersects the plane before the origin
- if d=1 then the vector intersects the plane at the end of the vector
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