Architect's site plan
Scale it by typing the real width of the drawing, then rotate until the roads
line up with the photography. On sloping ground raise the lift until it clears the
surface where you are tracing.
Existing buildings
Edit shape puts yellow corners on the boundary to drag, and the
corner buttons under Massing add and remove them. The cut and the pad re-sample when
you let go. Use Plan view to work on the outline from above.
Cuts the existing buildings out of Google's mesh inside the shape you draw,
so a new scheme doesn't grow out of the old roofs — instead of compositing two renders in
Photoshop. It removes the ground as well, so a flat pad goes in at the sampled height. Drape
the site plan over it and that becomes your ground.
Massing
Click a block to select it, then drag the yellow corners to reshape
it. Height and colour apply to the selected block, or set the next one before you draw. The
corner buttons work on the cleared area too, when that is the shape being edited.
Click round the footprint, then double-click or press Enter to close it.
Backspace undoes a point, Escape abandons it. New blocks take the height above.