VirtualGL is an open-source software package that redirects the 3D rendering commands from Unix and Linux OpenGL applications to 3D accelerator hardware in a dedicated server and sends the rendered output to a (thin) client located elsewhere on the network. On the server side, VirtualGL consists of a library that handles the redirection and a wrapper program that instructs applications to use this library. Clients can connect to the server either using a remote X11 connection or using an X11 proxy such as a VNC server. In case of an X11 connection some client-side VirtualGL software is also needed to receive the rendered graphics output separately from the X11 stream. In case of a VNC connection no specific client-side software is needed other than the VNC client itself.