I'm using Anim8or it's a free 3D Modeling program. You can find the program at
Anim8or.com
I use LithUnwrap to make the texture maps, and my favorite paint program to make the textures.
Basically the new trick I found is I can 'detach faces' to allow me to then create different groupings of objects.
The procedure is, make model, and once done, detach faces to make similar groups like the wings, the back end where the thrusters are etc. Export the model as a .3ds. Then import the model into LithUnwrap and 'select all' and under tools option make a uv map, (box is good for separating the parts). then play with resizing and positionning to make the maximum use of the bitmap area. Save the UV map, and save the model (again as .3ds) this new version of the saved model has the UV map info. Edit the .bmp of the UV Map you saved and fill in the parts with texture. then Import the model into Anim8or , you'll notice the model does not have the texture on it, we have to 'apply' the texture, using the materials menu, load the bitmap into the 'difuse' properties and allpy the texture. Because the model contained the UV Map it will know where to place the textures. resave the model as .3ds. now when you load it into LithUnwrap you can preview the model. Form this point on I have LithUnwrap and Artgem running, I tweak the texture map, and reload the model. it automatically loads the new tweaked texture map. preview, adjust,.. resave in the various formats .obj and .x for example. Oh and when I save the .x I select uncompressed text format, that way I can edit the .x file in notepad. this comes in handy when I convert the .bmp to .jpg for the final version. I simply change the filename extension at the end of the .x file and resave.
That's it in a nutshell, Hope this info helps, Cheers!
