Freestyle > Associating Elements on the Control Mesh > To Align Faces With an External Geometric Reference
  
To Align Faces With an External Geometric Reference
1. Select a face or a loop of faces of one or more shapes.
 
* If you have selected a combination of faces and edges, only the first selected mesh element type is aligned. The later selections are ignored. For example, if you select a face and then an edge of a shape, the edge is not aligned with the external geometry.
2. Right-click in the graphics window and select an appropriate align command. Alternatively, on the Freestyle tab click the arrow next to Align to perform these actions. Pull the dragger to adjust the alignment.
◦ Align—The selected mesh elements are aligned with the reference plane.
◦ Align Normal—The selected mesh elements are aligned normal to the reference plane.
3. Select one of the following external geometrical entities as a reference:
◦ Datum plane
◦ Planar surface
◦ Closed loop of edges
4. To change the direction of the tangent or normal connections right-click and choose Flip Direction from the shortcut menu. Alternatively, right-click the aligned region in the Freestyle Tree and click .
 
* After aligning the shape, you can change the alignment type or break the association by right-clicking the aligned region in the Freestyle Tree and selecting the respective command.