i made a software for a client and he got the intellectual property in the contract (btw, its a basic information system). If i want to sell this software to other clients, how much of it should i change in order to be able to sell it as my own?

Enough so that it isn''t a derivitive work. Consult a lawyer.

The hard and fast answer is that you''ll have to re-write the whole thing.

how about if i just change the user interface enough so that it looks like a diferent program, will that do the work?

I would guess that would still be a derivitive work - you''re still going to be using copywritten code that you don''t own the rights to anymore.

Again, consult a lawyer.

thanks, but i guess a layer might be a bit costly at this point.
Have anyone been in this situation before??

No, but offhand it sounds like you want to use code under someone else''s copyright to make your own product, so right away that sounds like it isn''t possible without permission from the owner.

That being the case, a lawyer is never too much.

IANAL, so don''t take my words as gospel:
If you don''t have direct control over the intellectual property in question (I think you are referring to the source code and the various graphics, logos, etc in the application), you can''t simply change it to make it yours. That would mean you derived your product from the other product.

You can reprogram it. Take the basic design (the idea is not under copyright) and rewrite the program. Take the opportunity to make it more extensible, make the code cleaner, etc.

Changing the interface will only change the interface, so it is still derivitive. You might be able to lie about it, but I wouldn''t suggest it. There are ways to determine what code was used to compile your binary file. B-)

But in the end, if you would rather not work this way, ask for permission to use the code in your product. See if you can get the right to do so without any repayment or something. Again, don''t be sneaky, like trying to get him to sign something without reading it or anything. Just ask, and work something out. At this point, you will probably need a lawyer anyway.

i guess i will have to re-code...

thanks for help!

The software you created is owned by the client you sold it to. That includes the code so just changing the interface would not be enough. Using portions of the code would be breach of copyright.

Getting a lawyer might be expensive but not as expensive as being sued by your client for breach of copyright. If you didn''t want to give away the code you should have negotiated a deal to license it to them or to sell it to them but with a license for you to create new products from it. You didn''t do that and now its too late. Making illegal use of their code would most likely be a bad move. It might prove very expensive and will also ruin any future relationship you might have with this client.

Learn from the mistake and move on. Use the knowledge you gained on this project to write a better product that you own and sell that.

Dan Marchant
Obscure Productions
Game Development & Design consultant