Tip guru Leonid Nemirovsky shares a method for dealing with strict clients who limit what you can do with layers in AutoCAD files.
"Our client is very strict about layers. I am not allowed to create layers with nonstandard names. Often I need one that does not print. A defpoint layer is an alternative for that purpose; however, to purge it I use –Purge, and Select All at the Command prompt, followed by Enter, then Enter again to accept * and N followed by Enter. Now everything that can be purged is purged, including the defpoint layer."
Notes from Cadalyst Tip Reviewer Brian Benton: Dealing with a client's layer standards can make our jobs a bit more difficult. Purging is definitely one way to clean things up before we send them the final files.
The layer DEFPOINT, by definition, will not print. It is automatically generated when you create an associated dimension. It's there to provide a nonprinting layer for the dimension nodes. Be careful when using that layer. It works in conjunction with layer 0, and if one or more of them is frozen or turned off, it will behave in a strange way. You are better off creating a layer that is set not to print. I suggest discussing this layering need with your client. Perhaps they will make an exception or add the nonprinting layer to their standard.