When creating a custom geometry and using MeshPhongMaterial as the material, I encountered an issue because of the size of my geometry. I wanted to merge them into one for better performance, but also wanted to apply different ambient colors to each child geometry. While I considered changing the color by using additional materials and altering the materialIndex for each face, I was concerned about potential inefficiencies and increased texture usage. Is there a simpler way to achieve this? I am unsure about how three.js renders with different materials, so any guidance would be appreciated. Thank you for your help.