Creo Interactive Surface Design (Style) > Connections > Curve Connections > To Define the Second Constraint for Curves with Surface Tangent, Surface Curvature, Surface Acceleration, or Draft Tangent Constraint
  
To Define the Second Constraint for Curves with Surface Tangent, Surface Curvature, Surface Acceleration, or Draft Tangent Constraint
1. Click Style > Curve Edit. The Curve Edit tab opens.
2. Click the collector. Select the curves whose tangent you want to edit.
 
* You can select only those curves that have the primary tangent type as G1 - Surface Tangent, G2 - Surface Curvature, G3 - Surface Acceleration, or Draft Tangent.
3. Click the endpoints of the curves to display the tangent vectors.
4. Click the Tangent tab and in the Second box, select the required secondary constraint type. You can also right-click the tangent and choose Secondary, and then a secondary constraint from the shortcut menu.
5. Click .
 
• You can constrain the control point tangents as well as interpolation point tangents.
• You can use Horizontal and Vertical for all the constraints, that is, for G1 - Surface Tangent, G2 - Surface Curvature, G3 - Surface Acceleration, and Draft Tangent.
• You can use the secondary constraint Normal only if the reference plane normal lies in the tangent plane.
• You can use the secondary constraint Align only if the curve tangent for the curve selected for alignment lies in the tangent plane.
• You can use Normal to Edge/Curve, Along U, and Along V when the primary constraint is G1 - Surface Tangent, G2 - Surface Curvature, or G3 - Surface Acceleration.
• You cannot use the secondary constraints Align, Normal, Normal to Edge/Curve, Along U, or Along V for Draft Tangent.