Hi Bob, I'll probably need to see the file in order to get any good idea of what might be wrong. Maybe the details are very small in numeric size and getting collapsed down?

re: Internal server error - if the file you're trying to upload is pretty large you'll probably need to upload it to a file sharing service like dropbox or Microsoft OneDrive and then just share the link to it here rather than uploading the large file directly here.

You would probably want to use STL format, it's pretty much the most simple format and there's less that can go wrong it it. OBJ should be ok too except probably not N-gons.

What you may be seeing is some model processing that Shapeways does to your file in order to account for limitations in the printing process - the printers have a limited resolution and so you can't print really tiny fine details that are below a certain size. Maybe they just sort of blob together things that are below a certain size threshold because of this limitation. That's probably my best guess.

- Michael