Tool: Lighting

The Lighting tool allows interactively adjusting several settings related to illumination, with sections:

• Lighting – key, fill, and ambient light settings
• Shininess – material properties of lighted objects
• Depth Cue – near-far shading of the scene

These and additional related parameters can be adjusted with the commands lighting and material, as well as by clicking icons in the Graphics Toolbar.

The Lighting tool can be opened from the Depiction section of the Tools menu and manipulated like other panels (more...).

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Lighting

The ChimeraX scene can have two directional lights, key and fill, plus ambient lighting. The key light is often the dominant source and can cast shadows; the first set of intensity, direction, and color values reported in the Log refer to this light. The fill light serves as a secondary directional source to improve the visibility of regions that would otherwise be dark. Regardless of whether shadows are on, the directional lights cause “shading,” where the brightness of an object varies based on the angle between the light direction and the surface normal. The key light also produces directionally dependent specular highlights. The ambient lighting is an approximation to omnidirectional illumination. Shadows cast from multiple uniformly distributed directions can produce ambient shadowing, or “ambient occlusion.” See also: lighting

Choices for lighting Preset:

• simple – all three kinds of light, but no shadows (details...)
• full – all three kinds of light, key light with shadows, ambient lighting with shadowing from 64 directions (details...)
• soft – ambient lighting only, ambient shadowing from 64 directions (details...)
• gentle – same as soft, except tuned to emphasize larger indentations (details...)
• flat – ambient lighting only, no shadows (details...)
  • this preset also turns silhouettes on; for silhouettes off, use or graphics silhouettes false

• Key intensity – key light intensity (adjust value with slider)
• Key color (a color well; click to adjust with the system color editor)
• Fill intensity – fill light intensity (adjust value with slider)
• Fill color (a color well; click to adjust with the system color editor)
• Ambient intensity – ambient light intensity (adjust value with slider)
• Ambient color (a color well; click to adjust with the system color editor)

The directional lights can be moved by dragging the color-coded solid arrows on the sphere: orange: key, blue: fill. The directions can be reset by choosing the simple preset.

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Shininess

The Shininess section of the Lighting tool adjusts certain material properties. See also: material

• Sharpness – specular exponent, which controls the spread of specular highlights (range 0.0-128.0, default 30.0; adjust value with slider)
• Reflectivity – the fraction of directional light that is reflected diffusely, equally in all directions (default 0.8; adjust value with slider)

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Depth Cue

The Depth Cue section of the Lighting tool adjusts near-far shading. See also: lighting options, clip

• Enabled – whether to use depth-cueing, near-far shading of the scene
• Start – the start (nearby end) of the linear depth-cueing ramp, expressed as a position relative to the near (0.0) and far (1.0) global clipping planes, which are shown/manipulable in the Side View
• End – the far end of the linear depth-cueing ramp, expressed as a position relative to the near (0.0) and far (1.0) global clipping planes, which are shown/manipulable in the Side View
• Color – depth-cueing color (a color well; click to adjust with the system color editor)