I'm currently working on my student architecture portfolio through InDesign CC. Several sheets contain line-work PDFs from CAD/Illustrator file links. When exported, the lines become thick and muddy. Any advise on how to keep line weights thin through exporting an interactive PDF from InDesing?
I think you'll have better luck in the InDesign Forum
Exporting to an interactive pdf gives the default resolution of 72 dpi. Try exporting it with a resolution of 300 dpi. Why interactive? When it contains lots of line-work images, just make a plain pdf with bookmarks, so you can navigate the pdf and keep the lines crisp.
You may also be seeing the effects of the "enhance thin lines" preference item in Acrobat and Adobe Reader (and who knows what in any other reader). If that's the case, you have no control over waht others will see on their own systems.