Using the Point/Vector FunctionKeyCreator \ Create \ Surface \ Point-Vector \ Using-the-Point-Vector-Function
To use this option you must prepare a grid of surface points or nodes and attach the appropriate slope control vectors if needed. Surface nodes may contain any combination of point, tangent, or cross vectors. A single point or a single vector, if properly located, is enough to define a node.
The Point/Vector surfacing algorithm establishes a smooth set of flow curves through the rows of node points to define the surface flow. The algorithm also uses the vector data at the nodes to control the direction of flow.
Four surfaces formed with different tangent and cross vector directions. Notice how surface slope is constrained by forcing the surface to be tangent to the vector.
Upon entering the Point/Vector routine, you will be prompted for the number of nodes in the U direction along each spline. Each spline must have the same number of node points. The node point and vector data does not have to lie in a straight line or plane. Since this data is used to define splines along the surface, it may traverse any reason able path necessary to model the surface.