I am currently working on some sheet metal parts and am modelling them as surfaces with the aim of converting after. I havn't used this method before and am already runing into difficulty. As normal i am creating a number of surfaces and knitting them together to form one. However, when i try to convert my surface to sheet metal it is as though Solid Works is ignoring the knit and just wants to for a solid from just one of my surfaces.

I did a test which i have shown in the image. As you can imagine, this is very easy to produce in sheet metal. To test it out i created the leg using a surface sweep, and the other surface with a fill. I knitted them together, and if i try to thinken it everything works fine. But if i try to convert to sheet metal solid works enables me to do so with th eleg but disregards the other surface. Any ideas???

heres the picture: