Blend
Curve on Face 
Insert
Wireframe Curves (Part Level)
Use this command to create
a blended curve on a face in a straight line between two points that lie
on the face. The straight line is projected normal to the face between
the two points. This
command allows you to span the projected curve across multiple faces.
Optional inputs include start and end tangents, using the
minimum face iso path between the two points, and a path point to locate
the plane of intersection along which the curves will be located. Refer
to the Optional Inputs below.
Face - Select the face to use for the starting point of the blended curve.
Start - Specify the start point.
Face
- 
Select the face
to use for the ending point of the blended curve.
End - Specify the end point.
Start tan - Specify a tangent direction for the start of the line.
End tan - Specify a tangent direction for the end of the line.
Use
Minimum iso path - Use this option to further define the path
the line should follow between the two points. By default, a theoretical
line between the two points is projected on and normal to the face.
Check this box to create a curve which follows the shortest path joining
the two points in the parameter space of the selected face (i.e., the
line that connects the projected endpoints in parameter space).
Path Point - Only use this option if the start and end points lie on different faces. It allows you to select a third point to locate the plane of intersection along which the curves will be located. Refer to the command description above.
