# Determining the line intersecting two planes

1. Aug 11, 2010

### doonzy

Hello,

Given two planes, P1 and P2, I would like to determine their line of intersection L. I know three points that lie on each plane: (p1, p2, p3) for P1, and (q1, q2, q3) for P2.

Based on what I am doing (triangle collision detection in 3D) it would be convenient to have L defined as a direction vector and a point.

Thank you.

2. Aug 11, 2010

$$\begin{pmatrix} a_1 & b_1 & c_1 \\ a_2 & b_2 & c_2 \end{pmatrix}$$