In Rhino, the [enter] key and the space bar, for most purposes, are identical in function. (The right mouse button also functions equivalently under most circumstances.)
[esc] (escape) Click two or three times in succession to cancel any command and return to the basic Command prompt.
[delete] is used to erase a selection.
[F1] brings up Rhino’s Help.
[F8] turns the orthographic lock function on and off.