To Define a Fixed Geometry Reference
1. In an open board part, click > > 
Model Properties. The Model Properties dialog box opens.
Model Properties. The Model Properties dialog box opens.2. Under Board, click change in the Fixed Geometry line. The Fixed Geometry dialog box opens.
3. Select a surface or edge as the fixed geometry reference for the part. The reference appears in the collector.
4. To flip the fixed geometry to the other side of the edge, click Flip.
 | The Flip command is available only when an edge between two nontangent surfaces is selected as a reference. |
5. Click Close.