I have two triangels (T1,T2) and their vertecies. I want to know the line at which the triangles intersect. For the vertecies I use SIMD3. It would be great if someone could help me with my problem.

I have plane from which I know a point and the normal. Both are SIMD3. I want to calculate a 2d coordinate system (directions of x and y in 3d space) , which makes scence to the User. The Planes can also be parallel to xy and so on. (But that is Easy). I also would be very thankful if there is away to get points which are on the plane to the 2D formt. I hope you could understand my english.