Intro: 3D-Printed Case for HTC One M8
Step 1: Printing
I used a MakerBot Replicator 2X. You should use rafts and supports because of the curved back. I printed it with the back on the top to get a better surface there. But this means that you'll need even more supporting structures.
It would also be helpful to use WillowFlex or another flexible plastic.
And well, all you have to do is printing out the .stl-file with a 3D Printer of your choice and afterwards remove the supports!
Have Fun :)