Creo Interactive Surface Design (Style) > Connections > Curve Connections > To Create Curve Connections Using Tangent Constraints
  
To Create Curve Connections Using Tangent Constraints
1. Click Style > Curve Edit. The Curve Edit tab opens.
2. Select a curve and click its endpoint to display the tangent vector.
3. Perform one of the following operations:
Right-click the tangent vector and choose a tangent constraint from the shortcut menu
Click the Tangent tab. Under Constraints, select a primary tangent constraint from the First box.
4. On the Tangent tab under Properties, select Fix Length or Relax Length.
 
* By definition, a Natural tangent has a relaxed length.
5. Type values for the tangent attributes.
 
You can specify elevation only for Free curves. When changing constraints, use the horizontal or vertical axis of the datum plane.
If the value of the tangent elevation angle is 90 degrees, modifying the tangent angle has no effect on direction. The elevation controls the tangent direction.
A draft measurement is available when you apply a Draft Tangent.
6. Click .