Hi guys I get this links from the Shiva3d Forum, I buy a license this same month, because in 3D it's a very powerfull tool for me...
Well, I found this 3 tools into the Shiva3D forum, and perhaps for someone can be usefully them are free and I think works only under Gimp...
http://www.katsbits.com/smforum/index.php?topic=527.0
http://www.katsbits.com/smforum/index.php?topic=528.0
http://www.katsbits.com/smforum/index.php?topic=530.0
I use Shadermap 2, it's not free but awesome and perhaps it's still interesting.
http://shadermap.com/home/
Thanks backslider seems very interesting...
The very few times that I needed to create a normal map I used gimp with this plug-in: https://code.google.com/p/gimp-normalmap/
I use the backslider tool and I go to buy, it's simply awesome, from a simple image this get the Ambient occlusion, specular, normal Maps, and the Diffuse, and you can touch a lot of things... It's really really interesting...
Another suggestion if anyone wants... for me the best modeler polygonal I touch... Silo it's a pay application but really I never touch a soft so quick for modeling and easy...
Take a look to Steam, they sell application , but the good point it's them are more cheaper than the official web of the software...
Silo in the official web its 120E in Steam it's 70... and now they have Modo Steam Edition, this it's a incredible modeler too, very used in USA.