# Convert a Quadrangle to a Triangle

1. May 14, 2012

### luonganh89

Hi all !

I got stuck in establising an method to Convert a Quadrangle mesh to a Triangle mesh (CFD).
I have a mesh file (.dat) which have information:
Number of Element - Node 1 - Node 2 - Node 3 - Node 4
1 1 2 3 4
2 3 4 5 6
Have anyone done like me. Can share me some information thank you so much

luong anh
pfiev

2. May 15, 2012

### gsal

You need to be more specific.
What exactly is the problem?
What is the method that you established and where are you stuck?

3. May 15, 2012

### AlephZero

The obvious thing to do is turn each quadrilateral into two triangles by drawing a diagonal. But if the quadrilaterals are curved (i.e. a 3D surface) the results may look different depending on which diagonal you choose.

If that is a problem, maybe you need to find the "center" of the quadrilateral (i.e. the average of the 4 corner points) and join that to the corners to make 4 triangles.

As gsal says it really depends what the triangle mesh will be used for.

4. May 15, 2012

### luonganh89

:D of course , I've just wanted to remesh my model, and i write a short code to remesh it and open it by using tecplot , but now i come back home , tomorrow i will send my result to you but i got some trouble @@