Projection

From ZBrush Info

The Projection panel controls projection of a normal map from one mesh to another of the same shape but with different topology.

We won't describe all of the controls in detail--many of them will normally be set in the predefined configuration files that ship with ZMapper. The most important ones are:

• Capture Current Mesh: This is normally the first button activated when projecting a normal map. It sets the currently selected ZBrush subdivision model as the source mesh from which a normal map will be calculated and projected. Once the source mesh has been captured, you should exit ZMapper, choose the target mesh in ZBrush, and come back into ZMapper to project the mesh.
• Create Projected Normal Map: This is used after the source mesh has been captured and a target mesh has then been selected. It calculates the normal map for the source mesh, and then projects it onto the target mesh.
• Release Captured Mesh: Once you've created your projected normal map, use this to set the captured mesh to none. This will restore the ZMapper display area and let you view the finished model.
• Raycasting Max Scan Distance: Sets the maximum distance ZMapper will cast rays from the source mesh as it tries to find a matching point on the target mesh. You may need to increase this if some parts of your models are not closely fitted.
• ShowMesh, ShowCap: At least one of these must be set. They control visibility of the target and source (captured) mesh, respectively.
• Allow Out, Allow In: If one if these is turned off, then ZMapper will not raycast out/in as it tries to match points on the source and target mesh. This may be useful if some points on the source surface can map to points on the target by both casting in and out. However, chances are that if that happens, your mesh has become folded in a way you didn't intend.
• Favor Out, Favor In: At most one of these may be set. If raycasting in both directions is allowed, then setting one of these tells ZMapper that the favored direction should be used if two target points are found, regardless of distances.

The other controls set how rays are projected. There should be little need to use these, but you can experiment if the default Normal setting does not provide satisfactory results.