I saw YouTube video, he use multimesh for grass and tree for our scene, and it's grass is animating. how to make muIltimesh animation and its possible to interact with them, I want to create interactable multimesh?
please help

    gd_qq Vertex shader.
    "Interactable" in what way?

        xyz how many ways to interact multimesh?
        I want whatever like raycast, area,
        collision body(rigid,kinematic) , or something

            gd_qq You can't do any of this with mesh instances, either plain or multi. You need physics/collision objects for that.

              gd_qq you need a shader. a good way is to send the player position to the shader and make the grass move in a certain way when it's close to the player.

              for making grass move by the wind, use a displacement/normal texture and apply it on a world UV (like triplanar xz) over the grass vertex.
              for making the grass react to the player you need to pass the player position, calculate distance, and apply a different displacement texture to make it move in a different direction.
              it's a fairly complex shader but achievable with some work.
              I won't write it for you, start with a simple vertex shader for wind and learn, then you will be able to do the player. it also involves a lot of math.
              you can start by creating a material with triplanar uv and pressing convert to shader, it will give you a starting shader to study.