X-ref.. Attachment Or Overlay

Usually When X-reffing I Set The "reference Type" To Attachment. However I Was Wondering When And Why I Would Set "reference Type" To Overlay?

when it is set to attachment, you have the ability to stack x-ref's, for example, you can place xref A into xref B, and then xref B into drawing C. Drawing C would then contain xrefs A and B.

if overlay was used in the above example, drawing C would only contain xref B

so if you use only one xref which would be better to use? i have always used attachment.

Thanks, Nbc And In Regard To Paul's Question Which Situation Is Less Constraining On The Program If You Are Only Going To Use One X-ref?

Thanks, Nbc And In Regard To Paul's Question Which Situation Is Less Constraining On The Program If You Are Only Going To Use One X-ref?

Overlay all the way.

I always Overlay. I never Attach because I don't like nested xrefs in my drawings.