To Align Two-Sided Edges with External Geometric References
1. Select a two-sided edge or a loop of two-sided edges of one or more shapes.
2. Click the arrow next to
Align on the
Freestyle tab to select one of the following align types:
◦ Align ◦ 
Align Normal 3. Select the external geometry reference. The external geometry can be an edge, curve, datum plane, planar surface, or a chain of curves or edges.
|  You can select external geometric references with G0, G1, or G2 continuity. |
4. Middle-click to align the selected mesh elements with the reference geometry. While aligning an edge or an open loop of edges with a closed chain reference, the segments of the closed chain will be highlighted. Select the required segment.
A glyph or connection icon is displayed on the referenced geometry when the external geometric reference is an edge or loop of edges.
| When a two-sided mesh edge is aligned with an external edge or a curve, 100 per cent hard crease is applied. Use the Crease slider or the spin box to adjust the crease level. |
5. To change the alignment type, right-click the glyph and click Position or Normal Position on the shortcut menu.
6. To change the scale of the glyph or connection icon, click Operations > Options. The Freestyle Options dialog box opens. Type the appropriate value in the Connection icon scale box.
7. To break the associativity between the Freestyle geometry and its associated external reference, click
Unlink. The glyph disappears from the referenced geometry.