A reader writes:
On Autodesk's Exchange Apps, I saw that you have an ebook. I thought about making an ebook as I have some exercise made up. (One shows you how to get the true angle on a drawing without drawing an auxiliary view.) I would like to know how you made your ebooks so that no one can copy them.
I didn't, because it is not possible to prevent PDF files from being copied. I have spoken directly with Adobe a couple of times about this flaw, but they tell me that it is not possible to implement this kind of security inside the PDF format. Well, we could add passwords for opening files, but this is irritating to the buyers -- and they can just pass along the passwords to others.
PDF files can be locked only when distributed through a PDF server, but this solution is only good inside a corporation because the locking occurs external to the PDF file -- and so it is no good for sales to individuals.
An alternative is to go with an ebook format such as ePub. Ebook formats can be locked to a reader if you go through sites like B&N, Amazon, or Kobo. The fundamental flaw in ePubs is they make a mess of formatting, whether simple text-only books or content-heavy titles like with CAD.
Copying PDF files is a serious problem in our industry, and it is the reason I have stopped updating my ebooks, except for commercial clients.