I have a simple model made of weldments. Just a simple W8x31 beam frame with some C8x18.7 perimeter. Well today I wanted to make a small change, add another piece of the W8x31 beam to it. I add a sketch line and select structural member and most of my structural member choices are gone. Neither of the two members actually in the drawing are even on the list anymore. I get 3 options for c-channel and I, W, H, beams none of them even are there anymore as a profile let alone different sizes. I'm running this model on 2015 and haven't changed a thing. Any ideas?