This section demonstrates how to construct a surface that is linearly extrude through a curve (Polyline, BSpline, Cubic Spline or Interpolating BSpline.
1. From the create menu, choose BSpline Curve, (Create -> BSpline Curve).
2. Start drawing the curve on the x/y plane.
3. Draw six control points in the shape of a hill.
4. After drawing six points, select the curve.
5. From the Right-Click menu, choose "Extrude a Surface", (Right-Click -> BSpline -> Extrude a Surface).
6. The surface will appear on the "positive" side normal to the plane defined by the curves' control points. The surface is attached to the curve which means that the surface will update if the curve is now edited.
7. The negative side of the surface can be extended by adjusting the "Min Extrusion" value in the attributes panel.
8. This will extend the surface on both side of the curve.
9. Surface can be converted into a normal BSpline Surface or Mesh for further editing by choosing the options on the Right-Click menu.
Creating a Ruled Surface >>>