Came across this tutorial on youtube - which makes creating a grass ball with fluffiness + under the effect of physics (wind, turbulence) so easy (crying..) - all in Blender.
Adding the Vertex weight mix modifier on the sphere (where the vertices are) can create this "cutting" effect. You give two sets of vertices (A + B) and tell Blender the factor, for this case, it is "subtracting B from A". Vertex Group A are the vertices on the sphere, and Vertex Group B are the vertices where you want the grass to be removed. So how to define group B?
The answer is "Dynamic Paint". In Dynamic Paint, you can define the canvas (where the paint takes effect), and the brush. Brush in this case is a cube that acts like the mow lawn.
So after getting this A - B group of vertices, by adding a particle systemSo after getting this A - B group of vertices, by adding a particle system on the sphere with hair as particle type, the hairiness of the grass will show up and it definitely made my day...SO FLUFFY.........
The grass material is based on texture image mapped with UV coordinates. Actually, at that point, I was already super satisfied with how the grass ball looked like because I have the exact same grass ball IRL but without this fluffiness.
The motto of the story is that you have got to "bake". If you don't bake, the rendered animation might not work, and you will die crying.
I figured adding a vacuum cleaner might make this more satisfying. Adding a super low-poly vacuum cleaner will do. There was this effect of cut grass flying along with the movement of the vacuum cleaner. This was achieved by adding another particle system but with Emitter as particle type. The cool thing about emitter is that you can hide the emitter :laugh:. Was thinking if a plane will do (with vertices on both side only, so the emitter can just emit from the vertices), and it did. Again low poly leaf as instance for the emitter will make the thing look great.
And lastly: Camera obsession. The movement of the vacuum cleaner and the plane emitter are along the same Bezier Curve. You can make their motion based on the path by "follow path". Same as the camera. It gives a nice close-up shot just behind the vacuum cleaner. But I overlooked the angle of the vacuum cleaner handle so it looks perpendicular lol.