To this end, select Edit , followed by Create Surface . Currently, this system restricts the number of rows and columns to 9 and the u and v degree to 8. Click on the buttons to make your selections. The surface will be clamped on both directions. After accepting your choice, this system displays the control net based on the parameters.
All control points are coplanar on the xy -plane and as a result only one row can be seen initially.
Then, rotations, translations or even zooming are required to bring the control net to a position so that all control points can be seen. You may also want to bring up the Tracing Window , if it is not activated, by selecting Windows followed by Show Tracing Window . Note that since each row has 5 control points and degree 3, the number of knots for each row is 9. Similarly, since each column has 6 control points and degree 3, the number of knots is 10. As a result, in the v -direction, we have four knots clamped at 0, another 4 knots clamped at 1, and two internal knots.