How to reset 2D drawings that have strayed into three dimensions

Hello. I am drawing plans and elevations and have found that when I view the drawings from the front ,back or the sides, many lines are actually crossing three dimensional space. I have tried using Projecttoplane with no success. Can anyone suggest a good workflow to rectify a drawing that has ended up like this? Many thanks.

Try using the SetPt command and only modify the Z value.

Generally that should fix it… Make sure objects/layers are visible and unlocked. Maybe post a sample file you are having problems with.

Thanks Helvetosaur. I have found that Projecttoplane projects to the plane that you are viewing. Is that correct? It seems counter intuitive but if I select the stray line in top view and then projecttoplane, it projects it correctly whereas doing it in the view that shows the discrepency (eg front) it projects the line to that plane.

Yes, that’s exactly how it works. It projects to the CPlane in the ACTIVE viewport.

Many thanks.