# Moller Tri Tri intersection

I'm done implementing Moller's tri-tri intersection routine. It gives you the location of where each triangle edge intersects the line of intersection between the 2 triangle planes:

Really you get the point location in the form of t values along the (really big) purple ray shown above. So you can tell if the triangle intersects if the t values are overlapping..?

That's what the paper says. But I can show you scenarios where the t values are overlapping, but the triangles don't intersect:

So I can't seem to figure out which edge value to discard.

The original paper is here: http://fileadmin.cs.lth.se/cs/Personal/Tomas_Akenine-Moller/pubs/tritri.pdf

• Can you explain more about what we see in the pictures and can you tell something about your implementation and the general idea of the algorithm? With the information we have now all I can say 'you probably did something wrong'. – Roy T. Aug 7 '13 at 18:10

BTW, there's Moller's sample code for this algorithm on the web (the link in the original paper is dead, but I found this one by following a link from the Real-Time Rendering intersection test table). The relevant part looks like the NEWCOMPUTE_INTERVALS macro.