Inserting a curve through points


1 After starting the Through Point Curve, select the curve you want to modify.



If the selected curve is a specialized curve and not a NURBS, the program asks you to confirm its conversion into a NURBS (unless you have deselected the Ask before converting check box).

Tolerance for converting into NURBS

You can control the way the curve is converted by setting a suitable Tolerance. The lower the tolerance value, the more accurate the resulting NURBS will be and, hence, the more control points it will have.

2 Choose one of the constraints you want to apply to the endpoints:



Fixed endpoints keeps the endpoints in the same positions.
Fixed end tangent leaves the tangent at one or both endpoints unchanged:
  • One — leaves the tangent unchanged at the selected endpoint only.
  • Both — leaves the tangent unchanged at both endpoints.

  • .
Fixed end curvature leaves the curvature unchanged at one or both endpoints:
  • One — leaves the curvature unchanged at the selected endpoint only.
  • Both — leaves the curvature unchanged at both endpoints.

  • .
3 Select the through points (by clicking on them or using a snap action).
4 End input.
5 Type the values of the Local factor and of the Propagation factor in the corresponding boxes.


Local factor and Propagation factor
The local factor controls the application of the change to the control points around the selected through point. The smaller the local factor, the smaller the section of curve modified, although the change is more marked. The propagation factor, on the other hand, proportionally controls the extent to which the change is applied not only to the section related to the interpolated point but to the entire curve.

 
6 Confirm by clicking Yes.



The curve will be modified.