[vtkusers] Where does documentation get built?

[David Doria]

I turned on "BUILD_DOCUMENTATION", but after I built VTK, I searched
for *.html files and I didn't see any. What am I missing? I was
expecting a Doxygen or Documentation directory (or something like
that) to be created in my bin directory.

I looked in the Makefile and I saw a DoxygenDoc target. I tried to
build it, but I get
error: cannot build VTK documentation without dot

What does that mean? And why wasn't this error produced when I ran
'make' (which should build everything since 'all' is the default
target).

Thanks,

David