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## Using display lists

VisIt benefits from the use of hardware accelerated graphics and one of the concepts central to hardware accelerated graphics is the display list. A display list is a sequence of simple graphics commands that are stored in a computer's graphics hardware so the hardware can draw the object described by the display list several times more quickly than it could if the graphics commands were issued directly. VisIt tries to make maximum use of display lists when necessary so it can draw plots as fast as possible.

VisIt decides when to use display lists and when to not use display lists. Typically when you are running VisIt on your local workstation with plots that result in fewer than a couple million graphics primitives, VisIt does not use display lists because the cost of creating them is more expensive than just drawing the graphics primitives without display lists. When you run a UNIXTM version of VisIt on a remote computer and display the results back to your workstation using an X-server, it is almost always advantageous to create display lists for plot geometry. Without display lists, VisIt must keep transmitting the plot geometry over the network to the X-server which then uses OpenGL to draw the geometry. By default, VisIt automatically decides when to use display lists and when not to use them but you can force VisIt to either use or not use display lists. If you don't want VisIt to ever use display lists, click the Never radio button under the Use display lists options in the Rendering Options Window. If you want VisIt to always use display lists, click the Always radio button under the Use display lists options.