The default axis number height is XNUMSZ, which can be changed with the SET XNUMSZ command before entering the 3DPLOT command, and changed inside the command by using the H key.
The current hardcopy device is disabled while the 3DPLOT command is active. The S key causes the current hardcopy device to be re-enabled, and the plot to be redrawn, thus allowing you to obtain a hardcopy, with the HARDCOPY comamnd.