In the example they didn’t actually model the leaves they are flat planes driven by a texture. They trick the look of depth by arranging the planes on all 3 axis’ so that no matter which way you rotate you see leaves. I did a similar thing for a quick model I did for a halloween challenge I did last year. Arguably could have spent a lot more time making it look good, but the cat tails feel like they have volume when they are just planes arranged at different angles.
https://sketchfab.com/models/b05f40a024fc431b8b12d367bd7f38da
