Im building an modular built Building. As the building is going to be massive I was going to using a overall UV map to drive the main maps and to increase the resolution of the model I was going have a second UV set containing more finer textures and dirt maps by overlapping UV Shells giving more pixels for each shell in the UV space. Is it possible for Unreal Engine 4 to power both UV sets through the model, if so how can it be done?
Yep, you definitely can. How you generate the UV unwraps will be down to the individual modeling software you are using, but you can import multiple UV maps in the .fbx file. In the UV mapping node in your material editor, in the details panel you can specify which UV index you want to use when mapping that texture sampler, or part of the shader.
Overlapping poly’s in a UV map is a perfectly valid and useful technique - just keep in mind that if you want to do any baked lighting, Unreal will need one UV index that doesn’t have any overlapping shells.
" In the UV mapping node in your material editor, in the details panel you can specify which UV index you want to use"
Where is this “details panell” where you can specify the UV index?
I´m in the “details panel” of the “Texture Sample” with an image, and I can´t find that “UV index” to choose wich UV channel I want to use…
I don´t know where is it… 
" In the UV mapping node in your material editor, in the details panel you can specify which UV index you want to use"
Where is this “details panell” where you can specify the UV index?
I´m in the “details panel” of the “Texture Sample” with an image, and I can´t find that “UV index” to choose wich UV channel I want to use…
I don´t know where is it…
