Okay, so I'm having a problem with some of my drawings.

I've got a part that's made with a molding process, and I have to actually show the tread pattern in the drawings. I've attached 2 .ZIP files with some more-or-less representative pieces. (There's 2 files due to size limits - I couldn't get a single file under 500kb.) They're made special for this thread, so there's a whole bunch of details that they don't include, but you'll be able to see at least what my issues are.

If you open the files, open COVER.IPT first, then roll the EOP all the way to the end. The other two IPT's are derived from it, so they'll need updating, as will the IAM and the IDW file.

Okay, now on to the actual problem:

I've modeled the base cover as a multi-body solid, and derived the solids into an assembly, so that the cover and the tread pattern are two different IPT's. This makes it very easy to turn the modeled tread pattern off in views where I don't need it. (You'll notice that in the top view of the cover in the drawing, the tread pattern is just done with hatching.)

However, in the colored ISO views, the boss wants to see the tread pattern. I've turned visibility on the edges off, and that's okay - when it prints, you can still see the colors and whatnot.

My problem is that I can create the drawings of the full-up part, but if I save them and close them, I can't open them again. The computer just sits there and thinks about it until I get bored and use the task manager to close Inventor after 45-60 minutes or so. The drawing file I've attached here will open on my computer, but the parts modeled here are missing tons of other detail.

Based on what you see in the parts and drawing files I've attached, is there a better way to do the tread pattern so that I don't have these sorts of issues? The solution is not to get a better computer - my workstation has the top end Sandy Bridge Xeon and 16 GB of RAM.

Any suggestions?

tread pattern.zip
tread pattern1.zip