Texturing a large object

Hello everyone,
until now I’ve only textured relatively small objects, such characters and props and stuff like that.
Now I’m starting to model bigger objects like buildings and terrains, but I really don’t know how to texture them properly. I mean: ok, I could grab a concrete texture and tile that on an entire wall, but what if I wanted to achieve a realistic result and paint a texture with variations… not a tiled one, not a procedural one… I can’t figure out the way to go: for example, I think that for a real-world scale building or terrain even a 4096 texture won’t be enough if I want to achieve a high resolution…

Can anyone help me throw some light on this please?

Thank you in advance,

The short answer is: You probably don’t. As someone with relatively little experience with this, but still some experience, is that you will want to use tiling textures plus decals and other manually placed overlays.

For example, let’s say you want to have an extremely large concrete wall, with some areas that have water stains, and others that have crumbled to reveal a brick core. You could create that with a basic tiling concrete texture, a wet concrete texture, and a brick texture. A lower resolution, non-tiling texture would be used as a mask, to control blending between the more detailed materials. That way, you could have a highly detailed wall, but without using a 12k texture.

You could also use UV decals as stamped-on segments of pre-baked variation, if you need a mask image as detailed as your textures, even better if you can use many instances of the exact same decal, maybe rotated and/or scaled differently across the wall.

Thank you @lolwel21, this was very useful. I’ll go deeper on decals, sounds interesting.

But while this kind of approach will do good for walls, what about a large terrain?
Do you use the same approach or something similar? Do you split the terrain into multiple pieces and texture them separately? Or is there a more correct approach in general?

I would do terrain in a similar fashion: I would still use multiple layers of tiled textures, mixed together and enhanced by hand-painted and/or procedural textures. For example, if you use an erosion addon, then the wetness and erosion vertex groups are extremely useful for shading. Due to the complex geometry of the terrain, decals won’t work as well, though.
Additionally, terrain very much benefits from complex particle systems, even if you want it to be barren. For example, you’ll likely want collections of pebbles at the bottom of cliffs, and strewn across the terrain in general.
Plants make it ever more complicated because you’ll want different varieties in higher densities in fertile, wet areas that receive a lot of sun, different plants in shaded areas, and different plants in dry areas. All of these should be particle geometry unless viewed from a long, long way away for maximum realism.