This video demonstrates how to use cross-polarization to between your light source and camera lens for improved metahuman photogrammetry results.
Real Human to Metahuman Photogrammetry video:
The Matrix Awakens: Creating the Characters video from Epic Games:
https://youtu.be/h_dJtk3BCyg
https://dev.epicgames.com/community/learning/tutorials/8kL9/unreal-engine-diy-cross-polarization-for-metahuman-photogrammetry