Help 'ObiCollider' does not contain a definition for 'idToCollider'

[josemendez]

First of all, thank you very much for your quick and accurate response.

My problem is that the number of particles released from the emitter is counting from before they hit the ground(here ground is designed as targetcollider).
I want to know the number of water particles that hit the ground.

That "hit" the ground, or that "stay" on the ground? when a particle is no longer in contact with the ground, does it still count?

and, i have a question, "the "targetCollider" variable is completely unused in the script." what does it mean?

It means the variable is declared, as if it was going to be used for something, but then it is not used at all in the script. It is not written to or read from, it just exists but it does nothing. It looks like you wanted to filter out collisions so that only those against a given collider were considered, but as the code is currently written, any collision with any collider is counted. I assume you copy-pasted code from several sources in a "collage" fashion, as there's other bits in the code that make little sense. Putting together code that you don't understand is a recipe for problems.