About copying pieces of filters...

Hey, guys.

Ok, moral question. Many of us crack open the hood on a filter to see how it's made, and there are some BRILLIANT FForgers out there. What do you do if what you need for a piece of your filter in progress is made by someone else, but it's not a 'snippit'. Can you legitimately copy that section as long as you give the person credit? Do you need to ask permission first?

The piece I copied for my filter is a large part of the other filter, but only a small part of mine (if that makes sense).

Thoughts? Do you need the filters to compare them?