Reparameterizes a NURBS surface.
To apply: Select a surface and choose Modify 
Surface Reparameterize from the Model toolbar.
To redisplay: Select the surface then choose Edit Properties Modeling Properties and click the Reparameterize Surface tab.
The way in which any point along the length of a knot curve is described in terms of the parameter U or V. Any given point on the surface can have different parameter values under different parameterizations.
Uniform. The difference between successive knots is equal to 1 regardless of the actual length of the knot curve segment.
Non-Uniform. The difference between successive knots is related to the length of each knot curve segment when the surface is created. However, when you edit the surface, the parameterization is not recomputed. Instead, the exact shape of the knot curves are preserved. You can manipulate surfaces with non-uniform parameterization more accurately.
Chord Length. The difference between successive knot values is related to the actual length of each knot curve segment. When you move a point, the parameterization is completely recomputed to preserve the relation between the length of the segments and the knot spacing. As a result of this recomputation, the edited segment jumps to a slightly different position when you release the mouse button.
Centripetal. The knot spacing is related to the square root of the length of each knot curve segment. In some cases, this may make smoother surfaces. As with chord length parameterization, the parameterization is completely recomputed when you move points, with the result that the surface may jump.
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