Menu item | Command | Description

Change z-coordinates to 0 | flatten | Usefull for turning drawings with 3d information into 2d. This command doesn’t flatten 3d solids.
Turn line into view | vl | This command turns any line in a 3d perspective view using current settings. Select a line. The endpoint closest to the pickpoint is used as the camera and the other endpoint is used as the target. Choose a viewport by left clicking with your mouse inside the viewport. When ready press Enter. Tip: Before drawing lines set elevation to 1600 [mm] so the lines have the right height.
Set lenslength | lens | Sets lenslength for 3d perspective view. 50mm is normal eye-lens.