How to join a set of non planar curves as seen here

Rhino Rhino for Windows
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1

hi.i have an issue joining this non planar closed curve as seen in here.how to create a solid surface out of this ??please help.
eng.3dm (14.0 MB)

2

eng_sweep2.3dm (249.3 KB)

3

which command did you use.how did you do it?

4

for the main surface I used sweep2 and for the ends I used patch.