Adding a Free Compound Spiral-Spiral Between Two Curves

2012-03-14

Product Documentation

Intermediate

Add a free spiral-spiral group between two curves that are in the same direction but have different radii.

The spirals have finite radii on either end. Spiral parameters and attachment points are automatically calculated. If either of the attachment curves (1, 2) are edited, the spiral-spiral group maintains tangency.

By default, the two spirals have equal lengths and A values. Both values can be modified at the time of creation by specifying a ratio of A1/A2 or L1/L2.

The spiral radii are identical at the spiral-spiral intersection point. The radius value is determined by the total deflection angle and the two spiral lengths. The radius value cannot be edited.

To add a free compound spiral-spiral (between two curves)

Click the alignment. Click Alignment tabModify panelGeometry Editor.
On the Alignment Layout Tools toolbar, click Free Compound Spiral-Spiral (Between Two Curves).
The current spiral definition is displayed at the command line. For more information about changing the default spiral definition, see Specifying Curve and Spiral Settings.
Specify the entity before and the entity after to which you want to add the spiral.
Optionally, enter a value for the ratio of A1 to A2, or select Length and enter a value for the ratio of L1 to L2. Otherwise, the A values and lengths of each spiral will be equal.

Note
If the curves are in the same direction, a compound solution is given. Enter Yes at the command line to accept the solution, or enter No to restart the command. There is no solution if the curves cross, or for concentric curves.