If you need to create a finial for a roof you may use Extrusions:
1. Save the finial half cut drawing as a preset. Here is a link to another quick tip about Custom Profiles:
2. Create a small circle with the Polyline tool.
3. Select the circle and go to Cadimage> Extrusions> Extrude along selected element.
4. Search the saved preset profile. Settings> Shape> Profile> Custom> Select the profile and click OK.
5. The resulting object will be a finial profile extruded along a small circle.