Automatic Unwrap Mapping group

These are options for how to flatten UVs when Use Automatic Map is chosen in the Objects To Bake rollout's Mapping Coordinates group.

Rotate Clusters

Controls whether clusters are rotated to minimize the size of their bounding box. For example, the bounding box of a rectangle rotated 45 degrees occupies more area than one rotated 90 degrees. Default=on.

Threshold Angle

The angle used to determine the face clusters to be mapped. Default=45.0.

As faces are gathered to be mapped, the modifier uses this parameter to determine which faces get put in a cluster. This is the maximum angle that can exist between faces in a cluster.

The higher this number, the larger the clusters will be, with consequently greater distortion introduced as a result of texture faces' proportions deviating from their geometry-equivalent faces.

Fill Holes

When turned on, smaller clusters will be placed in empty spaces within larger clusters to take the most advantage of the available mapping space. Default=on.

Spacing

Controls the amount of space between clusters. Default=0.02.

The higher this setting, the larger the gap that appears between clusters.

Automatic Map Size group

Rendering to texture can choose a map size for you. Automatic map sizing is enabled or disabled by a toggle on the Output rollout. The controls in this group specify how to create the map, when Automatic Map Size is enabled. Automatic map sizing computes the total surface area of all objects in the selection, then multiplies that value by Scale, and creates a square texture map of those dimensions.

Scale

The amount by which to scale the total surface area of generated texture. Default=0.01.

Nearest power of 2

When on, rounds the map dimensions (length and width) to the nearest power of 2. Default=off.

Min

The minimum size, in pixels, of the length and width of the automatically sized map. Default=32.

Max

The maximum size, in pixels, of the length and width of the automatically sized map. Default=1024.