Custom camo and 3D models

Hello. I have a question to people who make custom camouflages. I’ve seen some users that included a 3D render image (in Blender for example) of a tank with their camo. And I’m wondering if they made these models themselfes and just adjusted the UV map to the texture or they did it in a different way. I’m asking because I’m making a tank model and i wanted to adjust already existed texture to the model and then so i can either make new camo easier or add any camo i want. The problem with this is that these textures have a lot of elements and guesing everyone of them where they belong is kind of a pain so I’m not sure if they do it this way. I’ll be thankfull for any helpful informations.

I know this is a very late response.

In general it will be much easier for you to create your own UVW map and burn Ambient Occlusion and start from it as a base for your tank’s camo.
When it comes to WT camo system, I still have not figured it out entirely, but it uses separate seamless image for the camouflage pattern, while the details of the tank are painted over transparent background, at least for tanks.