Shininess Control allows interactive adjustment of shininess, brightness, and the color used for shiny highlights. These are material properties of stick, ball-and-stick, sphere, and ribbon molecular representations, MSMS molecular surfaces, and surfaces generated by Volume Viewer and Multiscale Models. VRML models (such as surfaces created by Surfnet) will not be affected.
Many lighting parameters interact with these material properties (see the discussion of lighting).
There are several ways to start Shininess Control, a tool in the Viewing Controls category.
Shininess can be adjusted by entering a value or moving the slider. Lower values yield larger, more diffuse highlights, while higher values yield more pointlike highlights. Slider values range from 1 to 128 (default 30.0).
Specular color is the color used for shiny highlights. It is added to the color that would be shown in the absence of highlights. If the color is already bright white, highlights will not be discernable; if the color is otherwise green and the specular color is red, the highlights will appear to be yellow. The specular color is a light gray (RGB 0.85,0.85,0.85) by default, but can be changed by clicking the color well and then using the Color Editor.
The preceding assumes that all light sources are white or gray (the default situation). Lights include their own diffuse and specular colors, which must be combined with that of the material.
Brightness can be adjusted by entering a value or moving the slider. It scales the intensity of the highlights. Slider values range from 0.1 to 10 (default 1).
Default restores the default values. Help opens this manual page in a browser window, and Close closes the Shininess Control interface.
The shininess is the OpenGL specular exponent. The effective highlight intensity varies as the cosine of the angle between the view direction and the direction of the reflected light, raised to the power of this exponent (see the glLight manual page for more details). The specular color components are scaled by the brightness, and the resulting values may exceed 1.
The Shininess Control extension modifies the Chimera default material properties. Stick, ball-and-stick, sphere, and ribbon molecular representations and MSMS molecular surfaces use the default material. It is not possible to independently control the shininess of different models that use the default material. In general, models that do not use the default material will not be affected. Although surfaces generated by Volume Viewer and Multiscale Models do not use the default material, special code in this extension updates their material properties.