Use 2D drawing for tracing
There is an option to place a 2D drawing as writing pad beneath your geometry. Elements supports BMP, JPG, GIF, or PNG files. To do this go to menu item Geometry.
Scale
You can decide here in which scale you want to import the writing pad. The displayed height and width of the image are the dimensions after the use of the scale = the dimensions it will have as a writing pad in the 3D model.