VMD User's Guide

Figure 5.1: RGB color scale: the three plots shows the contributions of each color, and the resultingcolors are on the bottom.Figure 5.2: The shift to the red component of the RGB scale caused by the value of “min”.• Opacity: a number (0.0 to 1.0) describing the transparency; 1 is solid, 0 is transparent. Bydefault, transparent objects are drawn with Opacity set to .3• Ambient: a value describing how strongly the material reflects ambient light. Ambient lightprovides a uniform illumination of objects with a background lighting of the object color.• Diffuse: Diffuse reflections are independent of the viewing direction, but depend on thedirection of the light source with respect to the surface of the displayed object.• Specular: a number describing the intensity of specular reflections. Produces highlights, thehigher the value, the smaller and the brighter the highlight.• Shininess: a number describing how large is the angle of the specular reflections. The smallerthe number the wider the angle and the more shiny objects appear. Default corresponds toa Phong exponent of 40.For details regarding these material properties, consult an elementary graphics book such as Foley& Van Dam (Computer Graphics).69