The Mapping Type parameter sets the direction and origin for the stretch. The mapping
types are Planar, Cylindrical, and Spherical. A planar mapping will stretch the texture horizontally from the center or YZ plane. Choosing a cylindrical mapping causes a stretch radially out from the center or Z axis.
A spherical mapping will stretch the texture radially out from the center or, in this case, origin. In all three mapping modes, the amount of stretch is 0.0 at the origin, then increases the farther away you get (from
the origin).
Setting the Absolute Flag parameter equalizes the stretch beginning at the origin. If it is not set (no check
mark), then the amount of stretch will be nil at the origin and increase continually as the distance from the origin increases.
The Distortion parameter sets the amount for the distortion as a percent of the maximum. You can link
this parameter to a generator to define a distortion profile. The value given to Scale Factor defines the maximum. The direction of the profile changes depending on the mapping type you choose. For Planar
mapping, the generator defines the amount of stretch in the vertical direction. For Cylindrical mapping, the generator defines the amount of stretch in a circle, around the origin of the stretch and starting
directly to the left of the origin. For Spherical, the generator defines the amount of the distortion from the origin of the stretch outward. When Distortion is not linked, the profile is sinusoidal.