User-Defined Graphics

Sometimes you may want to display graphics other than the standard molecular graphics. You may want to draw a box around a molecule, or an arrow between two atoms, or place a text label somewhere in space, or test a new method for visualizing a molecule. Because of the wide range of objects which can be displayed, VMD cannot be pre-programmed to display them all. Instead, it does offer a way to build up a new object from simple graphical items, including: points, lines, cylinders, cones, spheres, triangles (both with and without specified normals), and text. Since these are displayed in the scene just like all other graphics, they can also be saved to the various ray tracing formats.

This chapter describes how to use the text interface to add new graphics to VMD. It is broken up into four parts. The first is an introduction to the basic graphics available, the second is a tutorial which demonstrates many of the ways to use the graphics feature, the third describes how the base graphics command works, and the last describes the draw extension which can handle larger, more complicated objects.