This project achieved using Unreal Engine 4 and Granite for Unreal plugin that enables to use multi UDIMS to achieve high end texturing quality. One island takes up to 6 or 8 8K UDIM tiles. Granite is the most advanced texture streaming system, enabling you to handle massive amounts of texture data while using less memory and eliminating loading time. 

I have heavily relayed on using Substance Designer, which is the best tool for creating PBR textures. Using real 8k and 9k textures to create tillable textures in S. Designer, also as experimenting with cartoon style texturing. 

Unreal Engine 4 and Granite provides full ultimate texture solution for UE4, UDIM support ensures high quality assets imported correctly into UE4 and connected correctly in the material editor ready to be used.