4-vertex face diagonal

Ok, I was wondering if there is a command to switch the placement of the diagonal on a 4-vertex face. If it is between two of the vertices, it would be switched to the other two.

Gloume

You know, I had never though about that psudo edge before. I have no idea how to manipulate it. I just did some testing, and this edge is important if you use a low poly mesh for Sub-div sufaces, as it controls the curvature of the result mesh. I just realised I also would very much like to know about this.

-BetaParticle

Ok, scratch that last post, upon further, actual testing, this extra edge seems to have no effect on the sud-div mesh whatsoever. I’d still like to know if we can flip it or not.

ALT+J flips it. Unfortunately I’m at work now, with no Blender available to test it, but if memory serves me right… Select all four verts, then press ALT+J.

Actually ALT+J converts two triangular faces to one quad face…

If you have a quad face, there is no diagonal to flip. If you have two tri faces
then you have it… But changing that diagonal to the other won’t be solved by ALT+J…

Stefano

Actually ALT+J converts two triangular faces to one quad face…

OK. Maybe it’s CTRL+J then… As I said, no blender avail, cannot test.

And I got the impression that the diagonal was the result of having vert 1 and 4 of a quad being connected by an edge. That could of course be interpreted as two tris.[/quote]

Blaargh! I can’t find it. Can someone else help out here? I’m 100% positively sure there’s a hotkey for flipping a diagonal edge from verts 1-4 to verts 2-3 and vice verse. I can’t remember what it was, though. View sketch below. AAaahhrrggh!

From:

1–2
| / |
3–4

To:

1–2
| \ |
3–4

Mmmm…

A quad with two opposite vertexes joind by an edge is still a quad… YOu ca easily tell by Pressing the Draw Face button in the F9 window…

Anyway I’m not sure of ALT J and CTRL J either

Stefano

Ctrl+F

Ack! That’s it!

Ha! You’re right Ilac! I was actually talking about a quad with an implicitly defined diagonal, but I don’t know if it actually matters. This helps though! I was wondering because I know that subsurf works better on quads than triangles and thought that if you had a quad that was bent at a weird angle it would be good to be able to switch that invisible edge.