The credits sounds ok even if in the final version I would prefer it's based on the copyright notice of the application, i.e.
Graphics made with Sweet Home 3D , Copyright (c) 2005-2012 Emmanuel PUYBARET / eTeks
If you use free furniture listed at 3D models page, it would sound nice to add at least "et al"
Graphics made with Sweet Home 3D , Copyright (c) 2005-2012 Emmanuel PUYBARET / eTeks et al
If you use 3D models coming from elsewhere, check their license is compatible with the way you want to distribute your game.
Good luck to finish your game!
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Emmanuel Puybaret, Sweet Home 3D creator
