Re: GPL on rendered images

[Glenn Maynard <glenn@zewt.org>]

On Mon, Dec 13, 2004 at 02:10:30AM -0800, Don Armstrong wrote:
> 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]

In the above case, if the disassembled output becomes my preferred form
for modification--if it's what I actually use to modify the program--I
don't have to distribute the C source.  It's not useful for modifying
the binary I'm distributing, so it certainly can't be the preferred form
for modification.  That's one of the strengths of the GPL's definition
of "source": it permits the source format to change, not locking the
work into its original form.

> 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.

Within reason, sure.  In some cases, no; eg. for videos, where the
"source" material may be a lossless encoding, which is often a hundred
times the size of the video, well beyond my means to distribute.

-- 
Glenn Maynard