This was designed specifically for a portable air-conditioning unit but could easily be modified for any exhaust needs. Shared by NeilMonteiro on Thingiverse:

I designed this air duct to get the 120mm diameter exhaust from my portable aircon unit to fit out of my attic Velux windows without leaving a huge gap for my cats to sneak out of. It’s a pretty standard unit so probably fits other exhaust pipes, but I’ve included STEP and fusion files so you can customise it. Watch out for the clockwise thread on the tube.

Download the files and learn more

Every Thursday is #3dthursday here at Adafruit! The DIY 3D printing community has passion and dedication for making solid objects from digital models. Recently, we have noticed electronics projects integrated with 3D printed enclosures, brackets, and sculptures, so each Thursday we celebrate and highlight these bold pioneers!

Have you considered building a 3D project around an Arduino or other microcontroller? How about printing a bracket to mount your Raspberry Pi to the back of your HD monitor? And don’t forget the countless LED projects that are possible when you are modeling your projects in 3D!