How to fold a plane while keeping length of edges?

Question

Can someone tell me how to fold a plane (e.g. modeling a paper plane)? Because when I want to fold an edge (the middle line), but have the edges scale... Is there a way to have a pivot edge for the edge to turn around? I don't need it animated later, I just try to have a folded paper plane with correct texture afterwards.

I know how to get the 3D cursor as pivot point, but I need more of a pivot edge I think?

Also, is there a way to automatically get the folding pivot edges? So you can take a vertex and move it as you would do in real life with a sheet of paper?

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Ok, the trick is really pointing with the view through the folding edge path... The first fold worked - but the second one is a new problem: The selected vertice has to go to the crossing of the circle and middle line - with rotation of course because of the UV... So how can the folding edge be created/found? Is there a way to lock the edges from the selected vertice in terms of length?

Today I tried some geometry to accomplish the problem: generate the folding edge... but I don't know how to get a vertex in the crossing point of the 2 lines here (2 orange selected edges crossing - i need a new folding edge from top tip to this new point to fold the side) - Any suggestions?:

Answer 1

Welcome to Blender SE cheese!

While rotating the vertices around the fold, you must align your view so that the fold points directly away from the view. All vertices along the edge occupy the same point on the screen.

Now, you can set cursor to folding line, set pivot point to cursor and rotate.

Unfortunately, it is not easy to exactly align your view. If you need full precision you can create extra geometry and then align your view to it. Then remove the extra geometry.

Start like this:

Extrude a corner vertex at the end of the folding line. Right click directly to extrude it on top of the original.

Using the opposing vertex as cursor, scale the extruded vertex up some.

Now extrude that edge to create a face. Extrude the face to create a cube.

Select the face point away from the fold and hit Shift + Numpad 7. Now, your view is exactly aligned to the edge. Rotate the outer vertex.

NB! Extruding the edge the right way may be hard sometimes. You can experiment some and see. I'm not sure.

If you don't need exact precision. Align you view the normal way and rotate away.

Good luck!