optimise textures

[creasedpixels]

Hi Team - I have a VERY large model. Most of the model is green fields (English countryside) and a small part of the model is a nice old building.

When I create a 32,768px texture, the texture on the building looks nice (of course). But I need a smaller texture (6,144px) and when I create a smaller texture the building looks horrible (I understand, and aware of, the reasoning for this).

I wonder what the best process is for creating a very large model, with a small texture, but maintaining good texture quality in a SELECTED part of the model?

Is this even possible?

[SpaceGhost]

Just throwing ideas out here, but why not make your super high-res model of the building as a separate chunk, make your lower-res model of the surrounding countryside, then cut and paste the high-res building to replace the building in the low-res model. I'm not sure if this could easily be done in Agisoft beyond an inaccurate manual placement of the model (if that would even work with the textures) but depending on what kinds of reference points you have, this could easily be done by uploading the two separate models into another software like Rhino.

Just a thought!

[creasedpixels]

Thank you for the idea. I've had similar thoughts but it feels more like a workaround, instead of the actual workflow. (I'm hoping there IS an actual workflow!)...

Let's see if anyone else can offer any insight....

Thanks bro 

[Bzuco]

For this purpose I am using RizomUV, where you can manually, semi/fully automaticcally design UV model layout.
Their packing algorithm is great, so you can utilize as much as possible space in texture. It will also tell you what will be the pixel density and if you will be not satisfied, then you can increase texture resolution or add another texture(UDIM).
Also you can set for some model part certain pixel density and freeze that part of UV layout. RizomUV has a lot of functionality, it is swiss knife  .

Example of packing UV islands, 7x 8k texture https://ibb.co/0p79SJx