Selecting null area faces?

[Cervidellus]

I am trying to clean up some large and difficult meshes. The way we generate them produces a decent number of null-area faces. Is there a simple way of selecting null area faces without removing them? Most of them seem to get fixed by remove_t_vertices_by_edge_flip, but after doing this I want to check and make sure they are all fixed before moving on. In the GUI version, I am doing so by coloring the mesh by face area, and then selecting by face quality, but this feels a little awkward.

[alemuntoni]

Sorry for the very late reply!

You could use the per_face_quality_according_to_triangle_shape_and_aspect_ratio filter, using Area as metric, to set the area into the quality field.
Then, you could use the conditional_face_selection filter with condselect='fq==0', that will select all faces having quality 0.
Then, you can check the number of selected faces with the selected_face_number method of the Mesh class.