Creo Interactive Surface Design (Style) > Connections > Curve Connections > Defining Curve Tangents
  
Defining Curve Tangents
Define a tangent with the following attributes:
Direction
Length
Angle—Measured on the active datum plane between the horizontal tangent direction and the tangent vector projection
Elevation—Measured in degrees between the tangent reference datum plane and the tangent
Draft—Measured in degrees and available when you apply a Draft Tangent
You can drag a tangent vector to change its angle or length. The Tangent settings on the Curve Edit tab can constrain vector movement during dragging. Each tangent has a reference plane for constraining the primary and elevation angles.
You can set the following directional constraints:
Fix Angle—User-defined
Horizontal—Horizontal relative to the grid of the active datum plane
Vertical—Vertical relative to the grid of the active datum plane
Normal—Perpendicular to a user-defined reference datum plane
Align—Aligned with a reference location on another curve.
When you apply a directional constraint, you can change the tangent length.