Not Solid, just a "Joined Surface

 From:  NotSolidEnuf (WMEPARKER)
Hi All,
I did a quick search to see if this has come up before, and didn't find anything, but it could just be my search was wrong. I have two files with complex models, both are hundreds of surfaces. When you select the model, it does not say it is a solid, it says it is a "joined surface". However, if you use the select open curve function, the "N" key as it is known, no objects are highlighted, and no count of them shows in the status window. If you try to highlight solids, none come up, and the status window should show that when the model is selected. Is there any other diagnostic I can use to find out why MOI isn't calling this a solid?

Thanking you in advance,