Free MagicaVoxel: https://ephtracy.github.io/index.html?page=mv_main
Free Gaugan: http://gaugan.org/gaugan2/
You can take the specific 32 colors of Gaugan (for absolute control of materials) or any other, you can input a PNG (better for solid colors) or jpg formats!
Here with the "little double first image" jpg format!
So like a fractal process! Perpetual revival!