Displacement Maps in 4

From ZBrush Info

Displacement Map Submenu

The Displacement Map menu has been enhanced to have a behavior close to the new Texture Map menu.

The functions are the same as ZBrush 3.1 except that the Displacement map texture is generated and saved per ZTool or SubTool.

New features have been added:

• Clone Displacement, which will copy the current displacement map to the Alpha palette. This action lets you save your map or do other operations from the Alpha palette.
• Texture Thumbnail which displays the currently-selected displacement map or can be used to select a new one. To select a different displacement map, it must first be loaded into the Alpha palette. Then click the texture thumbnail found in the Tool >> Displacement Map menu and select the desired map from the popup window.
• Adaptive and DPSubPix may now be used together. Adaptive is a special calculation mode that in most cases enhances the quality of displacement maps; especially when the model has been sculpted with brushes that have the effect of moving points across the surface of the mesh. DPSubPix virtually subdivides the model to increase the number of points that are being calculated in creating the displacement map. For example, if you have a 1 million polygon model and wish to create a map sized 4096x4096 (which has up to 16 million points of data) you would use a DPSubPix setting of 2. This virtually subdivides the model twice during displacement calculation, resulting in 16 million points being calculated – a value that matches the resolution of the texture map. Higher values would add to the displacement calculation time without improving the map quality, because they would cause more points to be calculated than the texture could even hold. In short, only use DPSubPix when your mesh has fewer points than the desired map, and even then only use the minimum value that will match your texture resolution.
• Mid specifies the value that will be used as the 0 point for displacements. By default, this value is set to 0.5 which allows the map to depict both positive and negative displacements. You can adjust this slider to modify the map for positive-only or negative-only displacements.

The following settings apply to 32-bit map creation:

• Flip V tells ZBrush to flip the map vertically. This only works with the Create and Export Map button.
• Scale factor defines the baked-in map intensity.
• 3 Channels is required by some rendering engines, and instructs ZBrush to export three identical TIFF channels. This only works with the Create and Export Map button.
• 32Bit activates 32-bit displacement calculation mode. This will only work with the Create and Export Map button.

When creating a 32-bit displacement map, clicking the Create And Export Map button will provide you with a new dialogue that lets you specify where to save the map. These maps are exported directly from ZBrush, rather than appearing in the Displacement Map menu after creation.

Creating a Displacement Map which includes HD Geometry

The creation of a Displacement map which includes the HD Geometry is the same as a traditional displacement map, except that the HD Geometry slider must be at the maximum value, while the Subdivision slider must be at the lowest value. When the map is created ZBrush will capture all HD sculpted detail into the displacement map. However, you should remember that the finest detail will need a map of large size.