I've resolve my problem.
But, now, after studying a lot of time into 3DS and his bake feature, i found the X Wing Alliance model have more than 16 parts (objects).
This afternoon, i try to convert the Imperial Star Destroyer's texture within the Bake feature from 3DS.
3DS have generated 21 maps of 256*256, and when time come to put these maps on the ISD, I found the ISD have 21 objects.
So, i'll ask you, if i could have a special fs2 open built for models with more than 16 textures.
For now, i have only 3 models converted into Fs2 :
- the X Wing
- the new X Wing from the New Jedi Order
- the Tie Fighter



