Making Straight Cuts into a Trapezoid

Hi, I’m trying to make windows in walls that, due to an irregular building shape, form irregular trapezoids. The problem is that when cutting with CTRL-R, the dividing lines it makes seem to be composed of vertices that are averaged in between those of the lines they intersect, creating a skew in the divides that varies as you move them along the piece:
http://img198.imageshack.us/img198/4690/trapezoidcut.png

If the trapezoid’s length were aligned along some axis, one could scale the lines of the division to 0 along that axis, but alas most of these walls are rotated at an arbitrary diagonal.

So how can one specify that he wants it cut straight, as if with a knife that is perfectly perpendicular to the piece?

Thanks.

you could keep ends edges straight then modify it at then end

or you could add your loop then scale it along one global axis like X ect

or you could use the knife tools may be!

salutations

If the trapezoid’s length were aligned along some axis, one could scale the lines of the division to 0 along that axis, but alas most of these walls are rotated at an arbitrary diagonal.
If the object was rotated and its rotation was not reset you could set the orientation to Local and scale along its local axis (to scale along its X local axis you would use S X X)
If the rotation had been reset you can set the long edge to be a custom orientation from the properties panel (shortcut N)
Set this axis in the 3d view header and scale along it as if it were a global axis.

Ok, this may be the last resort as the pieces were not manually rotated but generated as a result of solidifying a 2D wall of arbitrary shape.

In reading that last part of your post I found the nifty View->Align View->Align View to Selected menu features, whereby pressing ie. Shift-NUM7 with the front face of the wall selected you can now face it head-on (albeit up-side-down). However when selecting the cut, I’m still not sure how to scale-squash it to only one local axis of my current view; if I hit S-X (or S-X-X) it still conforms only to the global X. Care to elaborate?

Try this… select a face along the wall. View -> Align View -> Align View to Selected -> Right (or Left). Change the Transform Orientation to View. Select an edge loop, then S-X-X-0 (scale to 0 along view X).

Beautiful, that did it.

Thanks, everyone. What a forum.