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Re: GPL on rendered images



On Mon, 13 Dec 2004, Glenn Maynard wrote:
> If you create a model, and render a PNG with that model, the source
> for the PNG is the model.  Okay, that's easy; we all probably agree
> here.
> 
> If I take your PNG, stick it in photoshop, edit it for a while, and
> save that to a PNG, what's the source?  I'd say it's the PSD file or
> the PNG; in any case, the model file is no longer relevant and isn't
> the source at all. 

I'm not so sure that this is the case. Consider the following
substitutions to your example:

Model -> C source
PNG#1 -> machine code
PSD   -> disassembly output
PNG#2 -> assembled dissassembly

It seems clear, to me at least, that the prefered form for
modification is both the model (C source) and the PSD (disassembly
output.) It's not enough just to distribute one or the other when
you've used both to create the final work, and I'd assume different
types of modification would require you to use one or the other.

As far as whose form is the prefered form for modification, unless
they're one and the same form, you really need to include both the
original modifier's (or creator's) prefered form, as well as any
subsequent modifier's prefered form. In the ideal (and commonest)
case, these forms would be the same. But when they're not, I see no
other way to completely satisfy the GPL than to distribute both.[1]


Don Armstrong

1: Even if you disagree if the GPL actually requires this, I'd hope
that you'd agree that it's best to include the type of information
that will make subsequent modification feasible, licensing arguments
aside.
-- 
There are two types of people in this world, good and bad. The good
sleep better, but the bad seem to enjoy the waking hours much more.  
 -- Woody Allen

http://www.donarmstrong.com              http://rzlab.ucr.edu



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