A short tutorial about how to design an assembly parametric using formula in CATIA V5.
At first, you must establish the main parameters that will change the all structure of an assembly (in this case, a screw, a nut or washer).
It is simple if you know what you want to do before you start. At first you must write what you need to do your assembly. In my example, I want to have a fixation with one screw, one washer and one nut. I want in part 1 of this tutorial, to change the thickness of the washer, and the assembly to be updated automatically without any changes made in the constrain structure.
Also, you if see the video, I made some 
changes, individually, for each part of assembly to have some rules for all parts from assembly. For example, if I want to change the screw diameter, I want to change the size of the nut and the size of the washer automatically. It is very easy to design in CATIA this type of rules for any assembly that you need.
MOST important thing, to be easier to use formula parametrization in CATIA, is to save the name of parts very suggestive, and to select with mouse the body of a part to display only the dimensions of this part, excluding all other parts that are in assembly (see more in video).
Read the dedicated article of how to use formula parameterization in CATIA V5 to understand better. If you have any questions ask me in the comment form.
You have explained in detail Parameterization in assembly module. I always follow your blog. Keep posting such articles. Thank you for sharing this information.