I'm learning to use Blender, for plan drawing by design projects. I'm very new in this program and not familiar with 3D design. I was working in the Edit mode for quite a long time and then switched to the Object mode. My object was totally different, but the render from Edit mode was still OK. I made quite a lot of "intersect-knife" by working on my object and I think this destructured my drawing. But can somebody explain this (look screenshots)? Now, a few minutes after this screenshot, the entire drawing in Edit mode is like this one in Object mode. Strange or not?