Creating a Curvilinear Distance Constraint

You can create a curvilinear distance constraint like any dimensional constraint of sketch.

This task shows you how to:

Create a Curvilinear Distance Constraint Using the Constraint Command
Create a Curvilinear Distance Constraint Using the Constraints Defined in Dialog Box Command

Before you begin: Create a spline and two independent points.

Create a Curvilinear Distance Constraint Using the Constraint Command

You can select two points and a curve and create a curvilinear distance constraint between the points of the curve. In this case, the distance value is displayed covered by an arc of circle indicating that a distance is created (that is reference/driven mode is activated).

Select two points.
Select the curve (spline in this case).
From the Sketch section of the action bar, click Constraint.
The curvilinear distance constraint is created. A green color arrow appears in the 3D area which defines the direction of the curvilinear distance measurement.

Position the dimension or click to end the command.

Before finishing the creation of the constraint, you can right-click on the constraint and select Toggle to change the direction in which the distance is measured.

Note: You can switch the direction in which the curvilinear distance is measured, only for the periodic curves.

The curvilinear distance constraint is displayed, an arc of circle is displayed above the value of the constraint and the CurvilinearDistance.x feature is created in the treeunder the Constraints node. If necessary, an implicit constraint is created between point and curve, forcing the points to be coincident with the curve.

Tips:

You can change the display of the constraint in Me > Preferences> Common Preferences > Object Properties > Constraints and Dimensions.
You can set the curvilinear distance constraint as reference when editing. In this case the constraint value is displayed between brackets, to inform you visually that the constraint is a measure.

Note: If you select a single spline and then click Constraint

, then, a reference curvilinear distance is automatically created on the limit points of the curve, indicating the total curvilinear length of the curve.

Optional: Right-click the constraint and select curvilinearDistance.x >Toggle to change the direction in which the distance is measured.

Tip: You can also toggle the direction of the distance measurement using the Toggle command from the context toolbar.
Optional: Double-click the created constraint to edit it.
The Constraint Definition dialog box appears with the value of the curvilinear distance. You can change this value, and also change the limit points of the curve. To do so:
1. Click More to access additional information.
2. Click Point.x component.
  The related geometry is highlighted.
3. Click Reconnect to redefine the constraint component.
4. Select another point and click OK.
  The distance constraint is modified accordingly.

Create a Curvilinear Distance Constraint Using the Constraints Defined in Dialog Box Command

You can create a driving curvilinear distance constraint using the Constraints Defined in Dialog Box command by selecting two points and a curve.

The curvilinear distance constraint is only available if both the first and second inputs are a point, and the third input is a curve. This order of selection must be respected scrupulously.

Select two points and a curve.
From the Sketch section of the action bar, click Constraints Defined in Dialog Box .
The Constraint Definition dialog box appears.
Click Curvilinear distance check box and click OK.
The distance between both the points is measured along the curve, and the constraint value is displayed.
Optional: Right-click the constraint and select curvilinearDistance.x >Toggle to change the direction in which the distance is measured.

Tip: You can also toggle the direction of the distance measurement using the Toggle command from the context toolbar.
Optional: Double-click the created constraint to edit it.
The Constraint Definition dialog box appears with the curvilinear distance value. You can type the required value or change this value using the arrows.
Click More to access additional information.
You can change the point to modify the curvilinear distance constraint if required.

Optional: Right-click in the Value box and select Edit formula to change the value.

Tips:

You can also right-click the curvilinear distance constraint displayed in the tree or in the graphic area and select CurvilinearDistance.x object > Edit Formula.
If you want the constraints to be created permanently, click Dimensional Constraints and/or Geometrical Constraints (depending on the type of constraint you want to create) from the Sketch section of the action bar. If you do not click these icons, the constraints will only be created temporarily.

The Formula Editor dialog box appears. It displays the three knowledge parameters available for the curvilinear distance constraint: Value, Mode and Activity.

You can specify these parameters constraint by a relation or a formula. You can change the mode of the constraint as Constrained or Measured and change the activity type as true or false.

For more information about knowledge parameters, see Knowledge Basics User's Guide.

Click OK to close the Formula Editor dialog box.
Click Swap location.
The orientation of the constraint is inversed, the second input point goes to the other side of the first input point. This modifies the shape of the curve and the sign of the constraint value is changed.
Important: The curvilinear distance constraint becomes inconsistent if the curve's support cannot be extrapolated or both the points are out of limit points of the curve.