I'm having some issues converting a surface into a solid. I have tried everything I know of. I have several surfaces all knit into one surface knit, that I need to thicken to .07 in. When using the thickness feature, I get an error saying that it is unable to thicken the surface. If I suppress the knit and then thicken each piece individually, they will thicken, but then I am left with a bunch of solids that don't quite meet up the way I'd like. I have also tried filling the opening on the surface, and then converting the surface to a solid with the intentions of shelling it, but the fill surface command won't convert it to a solid. Same with knit, if I try to close the shape. Any ideas? I have attached the part file. I'm still learning, so I'm sure the the way I'm doing this is pretty inefficient. If someone has a better idea, please let me know!