Doesn't need to be that high. But I don't want it to be a ditch either. 20-30 ft would be great. Like I mentioned before, the ideal area for the lightsaber practice area would be a courtyard or something like that. There's actually a place very close to my house that has a park with a nice little area that might work if necessary. But it's currently the meeting room and other locations that have to be indoors that are giving me the problems.