Some of my surfaces wont close. Can someone tell me why?

I know that if Sketchup doesn’t think my points lie in the same plane that it won’t connect them with a surface. I get that. But I don’t know how to find which points it thinks are not coplanar. I have a model (attached) that I’ve started but am stalled. I want to model a table made of 3 equilateral prisms connected as a bridge: 2 vertical legs connected by a horizontal prism. I am creating the prisms by placing quadrilateral cross section edging (shaped somewhat like a kite) at the vertices of the prisms and placing flat plywood boards between them. I’ve done other models to learn the correct miter and bevel angles to cut the plywood and the edging but I am having trouble getting the model to connect. How can I figure out what’s going on in the model and why Sketchup doesn’t like it? (One inside surface of the shortest edge piece doesn’t complete, and I can’t figure out how to extend the two boards to their full height along the angled top between the vertical edging.)
Thanks in advance!
3rdTry.skp (57.3 KB)

Some pictures of what you are talking about would be helpfuI. fixed some reversed faces (grey) and closed some loose geometry. But I am not really sure what you want…

3rdTry, rev.skp (59.2 KB)

It’s hard at those angles to measure why it’s not coplanar, but if you redraw the edge in a way that it is bound to be coplanar, it will heal things.

If you look in this video, I start to draw an edge from the bottom corner. As I inch up the slope, I held down the shift key. That makes it certain be the same angle. When I complete the edge at the top corner, the face fills in.

1 Like

Here’s a way of sorting these faces.

inteersect face