I recently bought the Samsung Galaxy Note II and noticed that there were not many cases available. So I decided to make my own. After doing this I thought it was a good design exercise and thought I would share it.
Step 1: Design phase
This is the most important part. To start with you will probably need a set of calipers so you can measure your phone. Input the length and width of your phone into Autodesk Inventor then extrude to the thickness so you get a block about the same size as your phone. Since we are going to make a case we want our block to be bigger than our phone by about the thickness of the case. So if we are making a case that is 0.100 inches thick then we need to add 0.200 inches to the length and width, and 0.100 to the thickness.
Step 2: Adding shape
Phones are not square. They have many curves and contours that need to be accounted for in our case. Measure the curves and angles of your phone and input them as fillets and chamfers.
Step 3: Is it a case?
So we now have an oversized phone simulate but it's not a case. The shell command will take care of that. Make your shell the same thickness as the extra you added in step one. 0.100 inches for example.
You may see that my thickness is 0.050, I found that with the Makerbot this is too thin to use due to strength issues. I recommend 0.100 or 0.150 if you are going to print it on a Makerbot.