VMD User's Guide

4/3 SCRHEIGHTi.e. 8.0YViewer’sEye PositionZXSCRDISTi.e. -2.0SCRHEIGHTi.e. 6.0Figure 4.5: Relationship between screen height (SCRHEIGHT), screen distance to origin(SCRDIST), and the viewer4.4.7 Graphics FormThe Graphical Representations or “Graphics” form controls how molecules are drawn. Molecules arerepresented by reps, which are defined by four main parameters: the selection [§ 5.3], the drawingmethod [§ 5], the coloring method [§ 5.2], and the material [§ 5.2.5]. The selection determineswhich part of the molecule is drawn, the drawing method defines which graphical representation isused, the coloring method gives the the color of each part of the representation, and the materialdetermines the effects of lighting, shading, and transparency on the representation.Draw Style TabSelect a molecule for editing using the ‘Selected Molecule’ chooser at the top of the form. Thebrowser below this chooser lists the reps available for the molecule. Each line of the browsersummarizes information about the drawing method, the coloring method, and the selection. Belowthis browser, choosers and a text input filed reflect the current state of the rep, and provide controlsfor changing the properties of the rep. Each drawing method has specific controls which will appearwhen it is selected. When the ‘ColorID’ coloring method is selected, a text entry box is shownallowing you to specify the index of a color to use for the selection, which may be a number from0to16.Changing a rep. To change a representation, select it in the representation browser. The atomselection for that rep will appear in the Selected Atoms text area and the controls will update toreflect the current settings. Changing the settings will immediately affect the displayed representationif the Apply Changes Automatically check box is selected. When it is disabled updates will only39