VMD User's Guide

• antialias < on | off >: Turn antialiasing on or off.• culling < on | off >: Turn backface culling on or off.• depthcue < on | off >: Turn depth cueing on or off.• projection < perspective | orthographic >: Set the projection mode to mode.• rendermode < Normal | AlphaBlend | GLSL >: Set the rendering mode to mode.This parameter allows the use of various OpenGL extensions to implement alpha-blendedtransparency, or programmable shading for higher quality molecular graphics. The defaultrendering mode does not enable these features since they significantly alter the rendering andperformance characteristics of VMD when they are enabled.• stereo mode: Set the stereo mode to mode.• nearclip < set | add > value: Add or set near clipping plane position to it value.• farclip < set | add > value: Add or set far clipping plane position to value.• get < eyesep | focallength | height | distance | antialias | depthcue | culling |rendermode | size | stereo | projection | nearclip | farclip >: Return the currentvalue of the requested option.• get < rendermodes | stereomodes | projections | details >: Return a list of theavailable values for the given options. (See section 4.4.6 and chapter 6 for more information.)• fps < on | off >: Turn frames-per-second indicator on or off.8.3.7 drawVMD offers a way to display user-defined objects built from graphics primitives such as points,lines, cylinders, cones, spheres, triangles, and text. Since these are displayed in the scene just likeall other graphics, they can also be exported to the various ray tracing formats, 3-D printers, etc.User-defined graphics can be used to draw a box around a molecule, draw an arrow between twoatoms, place a text label somewhere in space, or to test a new method for visualizing a molecule.The draw command is a straight Tcl function which is meant to simplify the interface to thegraphics command as well as provide a base for extensions to the standard graphics primitives.The format of the draw command is:• draw command [arguments]The draw command is equivalent (in most cases) to graphics top command [arguments], inthatit simply adds graphics primitives to the top molecule, saving you the trouble of typing an extraargument. However, draw extends graphics in two ways. First, if no molecule exists, draw createsone for you automatically. Second, draw can be extended with user-defined drawing commands.This is done by defining for a function of the form vmd draw $command. If the function exists, itis called with the first parameter as the molecule index and the rest as the arguments from theoriginal draw call. Here’s an example which extends the draw command to include an “arrow”primitive.97