Can anybody tell me how to fill the sections highlighted in blue in the photo? Notice that they are sticking out from the square plain at the back. thanks!

For a simple shape like that I would draw the diagonals with the Line tool otherwise you can use the Curviloft plugin.

Hi! Thanks, but if I use the line tool to draw diagonals, yes it creates a face but then you can’t erase the diagonals without it erasing the whole face - will the curviloft plugin allow me to fill the shapes without the diagonals? thanks!

The fact that you can’t erase the diagonals without losing the faces indicates the other edges do not lie on the same plane. Thus it would be impossible to have a single face bounded by them. That’s a fundamental law of geometry. Curviloft won’t overcome that. You can hide the diagonal edge so it isn’t visible but it must be there to have the faces.

I understand - how would I hide the diagonal lines? Thanks!

One way would be to select them and then hit Edit>Hide. Another way would be to hold Shift while clicking on them with the Eraser tool.

Awesome! I’ll give that a shot. Thanks s lot!

You might want to look at softening the edges too.Depending on the result you want Hide and Soften gives slightly different results.

Hide still leaves a ‘hard joint’ while Soften smooths out the edge.

Ctrl with eraser for soften.

Thanks so much - hide worked perfect! I’ll try soften as well.