create new data from trained ANN I use a very simple neural network to make classification between classes. Once my ANN is trained I'm able to present new and unknown data, and get a good classification. 

Is there a simple way to reverse the process and create an artificial data, knowing at which class it should belong ? 

What would be the method name ? 

Thanks a lot !
Of course you can create artificial data.  Simply pick the inputs to the neural network randomly; that's an artificial instance.  You can run it through the neural network and tell what class the neural network will assign to it.  That doesn't mean you know what class it should be given, or what is the correct class; there's no way to get that (you can't get something from nothing).