Filter quads out from triangles.

Hi all,

I have a mesh dome made up of a number of quads and a number of triangles. I'm trying to filter out which is which to deal with them separately. My end game is to be able to reconstruct all the quads so that they're planar. I've already got it to work for the 'flanges' of the triangular panels (they're quads).

I suspect what I'm asking is easy, in fact I have a feeling I've done it before using the face valence to create a mask but I'll be buggered if I can work it out again.

Any help greatly appreciated.

Kind Regards

Rob