Hello @Jesseaboyd,
A simple way is to use FILTER, you can select the entity type than need, in this case like this:
1. Search in the list polyline.
2. Add to list
3. Apply, then you will leave the box and you must select or cover the area for the entity to take, as we only look for the polyline, it does not matter if you cover more than the account.
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The polyline should be selected and, with it selected, you go to ISOLATE (4) in the lower right part of the screen to isolate it and make the surface you need, when you finish with it and you finish the isolate (5) so that everything returns again.
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Johanna Esteban
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Autodesk Expert Elite | Autodesk Certified Professional | AutoCAD Customer Council (Beta Tester for Windows & Mac)
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