Paint the grass, then change its mind

Johan Zhu made a small stylized grass tool with Codex and Three.js. You paint on the ground to decide where the grass grows, then twist density, noise, and direction. He calls it a work in progress that is already fun to play with. That is the right standard for a tool.

Grass in a scene is usually a material someone already configured. A brush is different. The picture changes because your hand did, and the sliders have to do what their names say. Direction that does not follow the stroke, or noise that is just a blur, would make the toy boring in a minute.

The feature is the instrument, not a finished landscape. You can see the grass listen.