I'm not really a maths guy so I'd appreciate any help on his matter.
I have three points in 3D that define a plane.
I have two vectors, that have their starting points in the 3D plane; in fact these two were used to define the plane.
I project the vectors on the plane so I have two 3D vectors that are in the plane. From here on the 3D problem could be reduced to a 2D problem and could be used using really basic techniques.
Question is: how do I do the last step - reducing the dimensionality from three to two? As the plane is a general 3D plane, I guess omitting one of the coordinates is not the way to go.