Extending Curves Controlling the Continuity of the Extension

In this example you will extend a curve to a point using the Extend Curve command and you will appreciate the different results you can obtain depending upon your Continuity By: choice. Open file "extend .e3".


 

1	After starting the Extend Curve command, select the curve to be modified. You will be asked to confirm whether you want to convert it into a NURBS (unless you have deselected the Ask before converting check box). End selection by right-clicking and selecting Continue.
2	In the Mode drop-down list, choose the Point option.
3	Select the point based on which the curve extension will be computed.
4	By selecting each option of the Continuity By: drop-down list, you can see the different results in the curve extension: First derivative Increases the length of the curve at the selected end point ensuring C-tangency at that point (C1). Second derivative Increases the length of the curve at the selected end point ensuring C-curvature continuity at that point (C2). Third derivative Increases the length of the curve at the selected end point ensuring C-torsion continuity at that point (C3). Fourth derivative Increases the length of the curve at the selected end point ensuring C-Curvature plot curvature continuity at that point (C4). Parameter Increases the length of the curve by changing the value of the parameter that describes it (each curve is described through a parametric equation as a function of a u parameter whose value ranges from 0 to 1). Tangency Increases the length of the curve at the selected end point ensuring G1 tangency continuity at that point.
5	Click or to confirm your selections and extend the curve. or Click to discard your changes.