keepfiles→False is an option for
qhull, which is a wrapper for the
qhull binary from www.qhull.org.
The interface between the Mathematica function qhull
and the qhull binaries is performed by transferring text files. Normally these
text files are deleted after the binary returns control to Mathematica, and their existence is completely transparent to the user. When keepfiles→True the
files are not deleted.