I'm creating a LEGO Mindstorms catalogue for a school project. I measured the LEGO parts and I made an average size. My goal is to create new parts with a Rapid prototyping machine and I wanted to make sure that I used the good dimension.
I don't know where you got that image, but you could always try and print the brick using the dimensions shown.
Using the brick (#32316) shown in your example it might be possible to produce a 3D model using the 32316.dat file that's available in the LDraw library. The next problem would be placing the brick in a model and exporting it as a file type that is actually compatible with CAD software.
I'm not sure how accurate the bricks in the LDraw library are as they're primarily for illustration purposes as digital models.