Lets you create a collar NURBS surface along any boundary of a mesh, or curve on mesh.
Create collar surfaces from meshes
Ribbon:This is the basic colllar mode. It uses the Tolerance you provide to determine the number of spans in the collar. It only fits the collar surface to the mesh along the boundary or curve that you selected, not necessarily over its entire width.
Surface:This mode gives you greater control on the resulting collar, by letting you put down more points, and specify the number of spans for each of the segments. It also creates collar surfaces that fit the underlying mesh at all points. This is the default.

Specifies the level of continuity possible at the edge of the collar surface, either Tangent or Curvature. Other surfaces can then be built from the collar and maintain this level of continuity with the mesh.
This option is only displayed if Fit Type is set to Ribbon.
Specifies the degree of the collar surface in the U direction. It can be either 3 or 5.
If checked, the tool automatically determines the optimal number of sample points to use for the fit. This is the recommended setting.
If unchecked, you have to specify a value for the number of samples in Num Samples.
This option is only displayed if Fit Type is set to Ribbon.
Specifies the number of sample points to use for the fit.
This option is only displayed if Auto Sample is turned off.
Specifies the width (in current linear units) of the collar surface.
Specifies a curve fit tolerance for the fit of the collar surface to the mesh. A larger tolerance usually means less spans on the collar surface.
This option is only displayed if Fit Type is set to Ribbon.
Specifies the number of spans for each segment you defined by clicking extra points on the boundary. The number of segments is equal to the number of points minus 1.
This option is only displayed if Fit Type is set to Surface.
If checked, the tool builds a periodic (closed) collar surface.
This option is only displayed if Fit Type is set to Surface.