Use Boundary Patch to create a planar or 3D surface from a closed boundary of edges. Apply conditions of tangent (G1) or contact (G0) to each edge, and preview the results before creating the patch. Once the first closed loop is selected, you can begin selections for a second loop.
Selections in an edge chain must be tangent continuous.
On the ribbon, click Construction tab Surface panel
Boundary Patch.
Select a chain of tangent continuous edges which define a closed loop.
To undo the last selection in an edge chain, right-click and select Undo Last Selection. Repeat when necessary to remove additional edges. To remove an item from the list, select it and press Delete.
Click the arrow under Condition to select a boundary condition for each edge or set of selected edges. Edges are G0 by default.
Optionally, select another closed loop.
Click OK to create the boundary patch feature.