Global Light Mapping

From ZBrush Info

Global light mapping is an efficient way to reduce the amount of system resources needed to light and render a scene. One global light map can replace many lights or free them for other tasks. You can use global light mapping alone or in addition to normal lighting.

The interface for global light mapping consists of diffuse and specular map previews and their associated intensity sliders:

For the Diffuse and Specular maps, click the preview icon to load an image from the texture palette popup.

Gdi: The Global Diffuse Intensity slider determines the strength of the global diffuse shading determined by the image above. The default is zero (no effect).

Gsi: The Global Specular Intensity slider determines the strength of the global specular lighting determined by the image above. The default is zero (no effect).

To make maps that can be used as described above to replace existing lights, create diffuse and specular bit map images:

1. Light your scene with as many lights as needed.
2. Make a new layer. See Layer Palette.
3. Hide the first layer and draw a white sphere with Material:BasicMaterial applied. See Material Palette. (You may want to do this with a copy of the BasicMaterial. See Material:CopyMat.)
4. Reduce the Material:Modifiers:Ambient value to zero.
5. Reduce the Material:Modifier:Global Ambient value to zero.
6. Reduce Material:Modifiers:Specular value to zero.
7. The white sphere, lit by your lighting setup, provides all the information needed for diffuse light mapping. Capture the scene with the MRGBZ grabber. (See Tool:MRGBZ Grabber.) The bit map will be added to your Texture palette.
8. Load the diffuse map by clicking on the diffuse map preview in the Light palette and choosing the map you just created.
9. Reduce the Material:Modifiers:Diffuse to zero and return Material:Modifiers:Specular to its previous value.
10. The white sphere, lit by your unique lighting setup, provides all the information needed for specular light mapping. Capture the scene with the MRGBZ grabber. The bit map will be added to your Texture palette.
11. Load the specular map by clicking on the specular map preview in the Light palette and choosing the map you just created.
12. Hide the current layer and activate the original layer.
13. Turn off all lights. Increase Light:Gdi and Light:Gsi until you duplicate the effect of normal lighting.

Using Global Light Mapping with existing lights

You can create interesting effects by adding to your existing lighting. For example:

Adding a diffuse light map at 50% intensity

To Learn About Shadows Click Here.

To Learn About Types of Lights Click Here.

To Learn About Placing Lights Click Here.