Lamp shade
thingiverse
I took FreeCAD for a spin and here's what happened. It was created to be 3D printed upside down with ease, no supports required.
Download Model from thingiverse
With this file you will be able to print Lamp shade with your 3D printer. Click on the button and save the file on your computer to work, edit or customize your design. You can also find more 3D designs for printers on Lamp shade.