Filling the gap between two surfaces

[alacerdaM9EPR]

Hi! I am fairly new to fusion 360, and was wondering if anyone could help. I used two meshes and sketched the outline of the meshes and lofted those as surfaces, so they both had smooth geometries and were no longer meshes. I overlapped those surfaces and I am trying to fill the gap between them.  I used the stitch command which combined just the top part of both the surfaces but did not fill or combined the bottom parts. I then tried to use boundary fill, but maybe it isn't considered a closed entity because it wouldn't let me select it as a cell. Does anyone have any ideas on how I can fill this gap while maintaining the geometries of both surfaces (the gap is not a consistent thickness since the geometries of the outer and inner surfaces that I'm trying to fill are different)? I attached the stl file so hopefully it's more clear as to what I'm trying to accomplish. Thank you!

[jhackney1972]

Please attach your Fusion 360 model you did all the work in.  If you do not know how to attach your Fusion 360 model follow these easy steps. Open the model in Fusion 360, select the File menu, then Export and save as a F3D or F3Z file to your hard drive. Then use the Attachments section, of a forum post, to attach it.

[alacerdaM9EPR]

Thank you! Here is the right file attached.

[jhackney1972 · Accepted solution]

Your model is extremely small!  I filled in the main body to make it a solid.  The Section Analysis is turned off in the model.  Model attached.