How do I create a part from a surface?

peter_paton

In the attached "bottom tray" I have sketched the completed item is showing as surfaces where I would normally see a part.  Is there a way to convert, or have I done something fundamentally wrong somewhere?  All other sketches/extrusions have ended up as parts which were able to be used in assemblies but not this one.  TIA  Peter

ISS NX418 Guards | Bottom Tray (onshape.com)

wayne_sauder

I do not quite understand the design objective with this piece, you had a part until all the delete face commands, I would recommend using a different workflow to delete unwanted geometry or avoid creating it if possible. 

John_P_Desilets

@peter_paton Are you trying to remove this potion of the model?  

peter_paton

Thanks John, I did eventually get there through trial and error.  The main problem was that I was not forming a part that I could use in an assembly, rather two surfaces.  However, I found that I could use these surfaces to do what I needed.  In relation to your question, I was trying to form a backing plate with two side pieces and a floor.  I used the shell command but that left a number of unwanted surfaces - I did manage to delete them in the end.  As for other workflow, I am still at the early stages of getting to grips with CAD in general and approached this from the perspective of not knowing what workflow options exist....

peter_paton

Wayne, I started with attepting to sketch the side pieces onto the backing plate face, but found difficulty in getting the floor to fit/dimension properly.  I tried again by sketching another rectangle on the face and using the shell command to leave the 2.5mm profile I wanted. This worked reasonably well but left a few elements that I had to then work out how to delete.

Having arrived eventually (if untidily) at a usable structure, I discovered it didn't form as a part that I could bring into an assembly studio to use there.

wayne_sauder

@peter_paton
I realize this may not be what you are after, but I found a little time to create this part with a different workflow. Feel free to look through this and discard any ideas that are no help to you. 
https://cad.onshape.com/documents/b293d18390dfb7468df8cf43/w/9d38c305a845ac6998d9d65d/e/d937bf0b3446332d4cd54762

peter_paton

Hi Wayne, I was busy at work when your reply came in hence the late response.  I have had a chance to look at it today, it is in fact very helpful. I haven't really looked at the sheet metal feature but your example shows that I ought to do so.  Many thanks.