Face from Curve Mesh
Insert
Shapes (Standard)
Use this command to create
a face by blending through a mesh of U and V curves. The curves can be
sketches, wireframe curves, curve lists or face edges.
The curves must intersect but do not have to be coincident at their end
points.
Parting lines can be selected as end curves of the curve mesh for tangent and continuous blending with neighboring faces. See below for continuity options.
You can select a single curve in the V direction if desired. The required inputs include the U and V input curves. Optional inputs include tangency at edges, refitting and the ability to provide a unique name for the face if desired.
U curves, V curves
Select the list of curves first in the U direction and then
in the V direction. When selecting the curves, pick points near the ends
of the curves to indicate the same direction. 
Parting Lines
are supported for end curves.
Continuity
Force boundary edges to be tangent and/or continuous with mating edges and faces. Select None, Tangent or Continuous.
Refit
Use this option to refit curves to help prevent abnormal characteristics such as creases to occur. The refitting is performed by approximating the curve with a new curve to a given deviation tolerance (see below). This option may be beneficial under the following conditions:
When rational and non-rational curves get matched in the profiles.
When the original curves contain too many control points (some imported curves).
When curve degree is too high (some imported curves).
Select from the following options:
None - Do not refit curves.
Tangent - The refitted curve is tangent continuous throughout its length.
Curvature - The refitted curve is curvature and tangent continuous.
Direct - An alternate more direct approach to refitting is applied. This can help even out parameter spaces for compound boundary curves to avoid "pinching."
Tolerance
If the Tangent or Curvature refit option (see above) is selected, specify the deviation tolerance for refitting curves.
Add Tangency
Use this option to add a continuity tag to the edge of one
or two mating faces that indicates the continuity at the edge.
Select the edge to tag.
If the edge is shared by two faces, select the face to tag. If you middle-click, both faces are tagged.
Select the continuity option.
Position - Only the position of the edge is maintained.
Tangent - The position of the edge and tangency (at the edge) are
enforced.
Curvature - The position of the edge, tangency, (at the edge),
and curvature (across the face) are enforced.
Specify the continuity magnitude (-1.0 to +1.0). This determines the amount of the face affected by the enforcement of tangency (i.e., how long before the face returns to its normal curvature).
Delete Tangency
Use this option to delete a continuity tag created with the Add Tangency option above. Select the edge that the continuity tag is attached to.
During the required inputs above you can right-click and select Make Curve List from the Input Options Menu. This will allow you to make a parametric list of existing curves to use as input for this command.
