Originally Posted by

**Alfredo Medina**
I'd like to add these comments and questions:

1) Instead of repeating

**(Ext radius + Radius) / 2**

every time you need it, it would be better to create a parameter such as "**x**", and make it equal to **(Ext radius + Radius) / 2** ; so you just type **x** instead of that formula again. That would make the long formula easier to read and to debug.

2) Notice that your formula won't do what you expect when **Diameter **is 700 or 1600 exactly, because you are excluding those values by doing this:

**and(Diameter >700, Diameter<1600)**

If the intention is "between 700 and 1600", shouldn't 700 and 1600 be included in that range?

if that's the case, a better solution would be:

**and(not(Diameter < 700 mm), not(Diameter > 1600 mm))**

which means "at least 700 and no more than 1600"

3) Shouldn't **Diameter**, **Radius**, and **Ext Radius** be related to each other by formula? It seems that **Diameter **can be changed independently without changing **Radius**, and vice versa, and it seems that nothing prevents the **Ext**erior **Radius **to be smaller than the *Interior ***Radius**.

4) Instead of Diameter, Radius and Exterior Radius, maybe you could have **Inside Diameter **and **Thickness**? just two parameters instead of three?