Autodesk Fusion 360 Parameters

Autodesk Fusion 360 adds a parameter to every dimension you add to your model whether you realize it or not.  These parameter are create consecutively starting with d1, d2, d3, etc.  Existing parameters can be reused in other dimension to add "parametric' features that can aid in controlling the model design.  For example, I have sketched a rectangular box with a length of 8 inches and a width of 6 inches.  I rename the parameters from d1 and d2 to Length and Width.  I then place another rectangle on top of the first which I want to be always half of the size of the first.  Using the existing parameters I simply add dimensions to the length as Length/2 and  width as Width/2 to accomplish this.  Every time I modify the first rectangle's length and width the second one will resize also.

Take a look at my YouTube video and you will see some of the possibilities you have with using parameters in Fusion 360.