# Thread: How to get an intersection point

1. ## How to get an intersection point

Hi, I need to know how to get the coordinates of an intersection point. I have the following situation:

An object and a line. The line hits the object -> now I need to figure out the exact coordinates where the line intersects the object (further on I need to know the distance of the origin of the line to this point of intersection, wheras I can calc it myself as soon as I got the coords of the intersection point).

How do I do that with OpenGL ?

2. ## Re: How to get an intersection point

Hi !

You can't do it with OpenGL.

But there are lots of tutorials on intersetions, most ray tracing tutorials also has useful information on this, have a go with google to find them.

Mikael

3. ## Re: How to get an intersection point

If you have the vector if the line i.e. point1-point2 then you also have the equation of the plane (object/polygon you are hitting) then you can work it out from this.... serach for point interesctin a plane, there should be answers for that on this forum. Working out which planes to check against is another thing though... so as Michael says check out raytracing stuff as this is exactly what that does.

4. ## Re: How to get an intersection point

Check out http://www.gametutorials.com/Tutoria...OpenGL_Pg3.htm which has 2 tutorials similar to what you want.

5. ## Re: How to get an intersection point

thanx shinpaughp, it is a great and helpful link -> solves my problem and more.

also thanx, to all the others who replied.

CU.

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