This case is really cool.
Step 1: Ultra Awesome iPhone 4/4S Case! (Step 1-4)
1- You will need to make a rectangle in SolidWorks roughly about 2.36in. in height and 2.5in. in width
2- Do an extrude to 0.45in,
3-Do a cut extrude to a depth of 0.38in.
4-Create posts in the middle of the border of the case that are 0.15in.