# Intersection between a plane and a line

1. Mar 10, 2007

### Asuralm

Hi all:
Given a plane ax+by+cz+d = 0, and a straight line, X = X0 + vt. What is an efficient way to compute the intersection point please? Also, is there any efficient method to determine if two points are located on the same side of the plane or on the different side of the plane???

2. Mar 10, 2007

### Tom Mattson

Staff Emeritus
I've moved your thread to the Homework Help section of the site.

As per the guidelines of Physics Forums, we would like to see your attempt at the problem before helping you with it.

Thanks,

Tom

3. Mar 10, 2007

### arildno

How to derive the answer should be obvious to you if you use a good enough notation!

Remember that for any t in R, there corresponds a point (x,y,z) on the line given by the equations:
$$x=x_{0}+v_{x,0}t, y=y_{0}+v_{y,0}t, z=z_{0}+v_{z,0}t$$

Furthermore, what requirement exists so that a point (x,y,z) is guaranteed to lie on the PLANE?

In particular, what equation for "t" do you get out of this?
(Remember that once you have found the required t-value, computing the specific values of the coordinates of the point is trivial)

Last edited: Mar 10, 2007