Parametric vs Configuration Variables article

alan_baljeu

https://learn.onshape.com/learn/article/parametric-variables-vs-configuration-variables

This article has a few points where the statements really could use demonstration or clearer example.  I managed to puzzle through a bunch, but this one has me stuck:

• Parametric variables allow a multitude of inputs because they are considered features. You can define the value of a Parametric variable off of a user inputted value, dimension, formula, another variable, or any combination of them.

I don't know how to use anything other than a formula.  How do I reference a dimension in a variable?

john_mcclary

Only way I know how to set a dimension to a parametric variable is to create the variable in featurescript.

here is the most common example: https://cad.onshape.com/documents/77baa8153589a7fc5f289829/v/ceb4a03e4ac77173bf6d0074/e/181cb871f3008e6b885df46a

romeograham

The other way to "use" a dimension as a Parametric Variable is to use the excellent Measure Value featurescript.
You can use it to measure the dimension you want to use later, and create a variable that you can use directly, or however you want later.

Here we have a dimension (5cm) that we want to use later as a variable:
Then we use the Measure Value FS to create a Variable (I called it #length) to use later:

Now, #length is available to use any way you'd like. We can use it to set the length of a blind extrude:

Or as a variable in an expression:

...which updates nicely when I change the dimension in the first sketch:

You can use the Measure Value FS to measure quite a few different things.

One of the interesting things about Parametric Variables, too, is that you can set a new value further down the Feature List. Onshape will solve for #length using what ever value is valid at that point in the Feature List:

You can even use a Variable inside itself. This is useful for accelerating or variable pattern work (search for @NeilCooke 's "pretty patterns" posts / documents and this webinar for great learning materials).

Good luck!
Romeo