Using Compiz with FreeBSD

For setting up X server follow instructions here. (Long story short, use nvidia driver, add glx and extmod extensions to xorg.conf, and add argb-glx-visuals to monitor.)
To start compiz don't follow their instructions - rather open gnome configuration editor, browse to /desktop/gnome/session/required_components and change value for windowmanager to be compizmanager (instead of metacity, also make sure there exists /usr/local/share/applications/compizmanager.desktop (executing compiz-manager)).
If you don't see windows borders after restarting gnome, make sure windows decorations in compiz are enabled (Effects section of compiz settings).