Performs a powerful editing of any NURBS curve.
User can specify position, tangent direction and curvature radius at any point of a curve both interactively and by numeric input. In added, these values can be set equal to the values relative to a point of any other curve. Curves can be edited even if they are a result of an action.
How to use
1. Click the Advanced Curve Edit icon or choose the Tools > Transform > Advanced Curve Edit menu command.
2. Pick a point on the curve you want to edit and drag it to individuate the exact position. When in Edit mode, the tool shows the position, the tangent direction and the second order derivative direction of the curve at the specified point.
3. Pick and drag the Position, Tangent or Curvature hot-spots to interactively change the local shape of the curve.
4. To change the point of the curve to edit click near (not on) the Position hot-spot and drag it in the desired new point.
Note I: The length of the tangent direction vector is proportional to the curvature radius.
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Note II: The curvature vector is, from a mathematical point of view, the second order derivative of the curve in the specified point. The length of this vector influences the curvature radius; its direction defines the changes of curvature radius locally.
Note III: To reduce the influence area of this tool, you can add control points to the curve near the point to be edited.
Options
Object
To change the curve to edit.
Views / Modeling Tool panel. Switch the Replace check button on and pick another curve in the scene.
Parameter
To set the parametric point (in the range [0..1]) of the curve to edit.
Modeling Tool panel. Set the value either by moving the slider or by typing it in the data field and pressing Enter. Value must be between 0 and 1.
Point
To set the new position of the specified point on the curve with respect to the local coordinate system..
Modeling Tool panel. Type the new values in the XYZ data fields and confirm them by pressing Enter.
Tangent
To set the new tangent direction and magnitude of the curve at the specified point. Note that modifications of the tangent magnitude (length) influence also the curvature radius.
Modeling Tool panel. Set the value either by moving the slider or by typing it in the data field and pressing Enter.
Curvature Radius
To set the curvature radius at the specified point.
Modeling Tool panel. Set the value either by moving the slider or by typing it in the data field and pressing Enter.
Constraint to Object
To set position, tangent direction and/or curvature of the selected curve at the specified point equal to those of a reference curve at a reference point.
Modeling Tool panel. Switch the chosen radio buttons on. Options are: Position, Tangent, Curvature.
Reference Object
To specify the curve to which refer for position, tangency and curvature radius settings.
Views / Modeling Tool panel. Switch the Replace check button on, pick a curve in the scene and, holding down the mouse button, position the reference point on the picked curve.
Reference Point
To specify the point of the reference curve. The point will be projected on the reference curve.
Views / Modeling Tool panel. Type the new values in the XYZ data fields and confirm them by pressing Enter.
Reference Parameter
To set the parameter of the reference curve.
Modeling Tool panel. Set the value either by moving the slider or by typing it in the data field and pressing Enter. Value must be between 0 and 1.