I have a mesh I generated by converting a beveled curve to a mesh. The result is very useful, but I would like to make one curved part of it flat. Can this be done without selecting each face and moving it?
You can do this fairly easily if you use proportional editing and scaling.
Turn on proportional editing:
Select the top layer of vertices using box select:
Scale (S) along the Z axis (z) then press 0 to scale it it flat. Scroll your mouse wheel to adjust how much of the mesh it affects:
And you get:
If your curve isn't flat like in the previous example, it's still possible, it just takes a little more work.
Select the edge loops around the area you want to flatten (using Alt Right click):
Pull them out to be flat with the middle edge loop.
Shift-Select the middle edge loop and push all of them in:
Continue tweaking it until it's flat enough: