Add a Tangential Constraint
General
- You can define a tangential constraint between arcs, circles and surfaces.
Add a tangential constraint to a 3D sketch
- Select the function 3D Sketch | Constraints |  Add tangential constraint or Add tangential constraint or- select the context-sensitive function  Constraints > Constraints > Tangent. Tangent.
 
- select the context-sensitive function 
- Select the first line.- This line remains in place unless the other line is locked in place with constraints.
 
- Select the second line or face.- This line moves so that it (or its extension) is tangent to the first line, unless the line is locked in place with constraints.
 
- Repeat steps 2 and 3 to add new tangential constraints
- Stop adding tangential constraints- Select another function or
- press the V key or
- press the Esc key or
- click the middle mouse button.
 
Note: 
      
  - You can delete a tangential constraint by deleting it from the constraint list.
