I'm trying to make a grass cutting animation. A blade rotates and when it collides with grass, I want to replace the grass object with the sliced variant.
I tried the particle system with 'die on hit' ticked, and to the blade I added collision with 'kill particles' ticked, but that didn't work. But even if it worked, I still don't know how to replace them.
Sample video: https://youtu.be/YpSQlPAyW3g
Some kind of illusion can be done with boolean operation. You can start with Geometry Nodes to create grass object ...
... but final "cut" is boolean operation (grass differenced with Circle object displaced by Radial Texture), that results in glitchy anim (doesn't matter if I use boolean operation inside GN or as modifier).
What solved this is Solidify modifier for grass object, but in cost of viewport playback (1 fps).
Falling parts are particles emitted from Blade object ...
Another illusion can be done with two exactly the same overlapping particle systems.
One with tall grass and hidden blade on plane surface level to kill particles ...
... in combination with second one identical Plane. The only difference is Render as Object with shorted grass model.
This gives you an illusion
Falling cute grass can be faked in the same way like in the first version.
Notes:
