Trying to make a layer on satellite imagery

I have a fairly large terrain with satellite imagery over it, G. Earth style (via world compositor for Unity engine), but I would like to paint over it, not to just delete the satellite imagery, but to keep it temporarily, so that I know where the houses and stuff should be, so basically I want a multilayer material/texture or something, with one layer being the imagery and the second layer being my painting, is that possible?

Also, how should I go best with increasing the resolution of the painting textures? Since it’s a satellite imagery, when viewed from a human height, the ground is all blurry, it’s only good if you look at it from the air, but I want to create something like a game level. Should I cut the terrain itself in a bunch of small sections and create a separate 2048 texture for each of them? Currently I just have one huge 8192xsomething texture.

Note that I never really touched the paint section of Blender, I only dealt with materials and uv textures, so dumb it down a little.

This is how it looks as of now, the area covered is something like 1.6x1.6km (or mile x mile)

No one? I figured out that the only easy way, without using nodes, to keep textures unified in size when painting them, is to paint them inside the uv editor, instead of the 3d view. In that case the texture size is changed via the brush size option. It shouldn’t be, but meh, it’s something, painting in 3d view gives you a different result even if you move or rotate the camera even a little and you don’t have any control, but that’s another topic.

So, since I figured out how to get somewhat uniform sized textures, I realized that even if I make them very small, they get destroyed due to pixelization, for example sand on the beach (photo in first post), since it’s such a large terrain and even a 16k texture doesn’t help.

If I had a supercomputer, I’d just put a +100k texture and I’d solve the problem, but as of now it’s probably the best to separate the map into a bunch of smaller parts and assign each one a 2k texture. I can split them, but what I don’t know how to do is how am I supposed to export those parts of the texture as separate images, so can anyone help?

I know how to cut&crop stuff in Photoshop, but perhaps there’s a way to crop a used part of a texture in Blender automatically. If there is none and if I have to use Photoshop, is the most efficient way for this to use the UV layout as a guideline to crop the exact part of the texture I need?

I would export the UV PNG and then take it in Photoshop so you can use layers with like 50% opacity so you can see what you are painting over then when happy with what you covered then you can merge it and export it. Use that back in place of the previous UV layout without the painted areas.

I haven’t really understood, do you mean that I should paint in Blender or paint in Photoshop?

Btw, I don’t care about the layers that much anymore, what I am obsessing over now is the size of textures, pixel density to be more precise. Do I just go on each 10 or 100 meters and create a new texture and repeat that process a gazillion times or is there a smarter way to do it?

I have this thing where I calculate pixels per meter, for example if I put a 2048x2048 texture on a 10x10 meters block, then that means 2048 pix / 10 meters - 204 pixels per one meter and that is…good. Anything lower than 100 pixels is way too low res and you can’t paint textures with it, I mean you can, but you see a ugly mess. For example if I take a 75x75 m block, like you can see on the upper image, then I need at least a 16k texture to achieve the same 200 pixels per one meter density, 8k gives me a 100 pixels, but that is not really good. Covering that entire terrain with a bunch of 16k textures would be pure madness and having to do several times more work by putting 2k textures on smaller terrain sections would be even crazier.

So is there a way to make the entire terrain “paintable” (density of 200 pixels per meter) without having to crate 10’s and hundreds of texture images for each tile and if so, would that process allow me to export such made terrain in Unity and Unreal?

I used Open IV to look at GTA V’s internal files and textures and I saw that terrain 3d models only have 512 or 1024 seamless grass/sand/etc. textures assigned to them, but not an actual painted texture, so they are using something, perhaps the textures Atlas thing or whatever it’s called?