To Substitute Geometry
1. Click Flexible Modeling > Substitute. The Substitute tab opens.
2. To select the geometry to replace, perform one of the following actions:
To select surfaces, intent surfaces, or both:
Click the Substitute references collector, and in the graphics window, select surfaces or surface sets from multiple bodies and quilts, an intent surface, or both.
The default is to collect surfaces. On the References tab, you can see that Substitute surfaces is selected.
To select edge loops:
1. Click the References tab, and select Substitute edge loops.
2. Click the collector under Substitute edge loops, or click the Substitute references collector on the Substitute tab, and in the graphics window, select one or more closed loops of one-sided edges of one or more quilts.
3. To select surfaces to replace the substitute references, click the Substituting surfaces collector, and in the graphics window, select surfaces of a single body or a single quilt.
4. To substitute the selected rounds and chamfers that attach the substituted geometry to the model, check the Transform selected attachment rounds/chamfers check box. If you do not check this check box, the selected attaching rounds and chamfers are removed and optionally recreated.
5. To set additional attachment and propagation options, right-click and use the shortcut menu or use the Attachment and Options tabs.
6. To navigate through other possible solutions for geometry configurations, on the Attachment tab, click Next or Previous.
* 
When you click Next, the system might stop responding while it tries to find the best possible solution. This is because it checks for all possible combinations for the solution. The system might also stop responding if a solution does not exist.
At this point, to interrupt the check and continue working:
1. While the model is regenerating, click Stop at the bottom of the window to interrupt the regeneration. A failed feature is created.
2. In the Model Tree, click the failed feature and select Edit Definition. Even if you do not make any changes in the settings, this gives you the opportunity to check if the result is what you want.
3. Click OK. The feature regenerates.
When the system is unable to find more than one solution, the Previous and Next options are not available.
You can select a different solution when you redefine the Substitute feature.
7. Click OK or middle-click to create the substitute feature and quit the tool.
* 
Currently, the original appearances of the substituting surfaces or quilts are not preserved by the Substitute feature. Upon feature creation, the substituting surfaces will display the model default appearance.