Particles Change Color on Collision?

[Chrissonator]

@ Chrissonator
Surface test is your friend.
Just use that operator and reference the object that will change particles (you have various options: Distance, volume inside, volume outside), and just send particles to next event with different color (or material).
If you have some forces (wind, speed.. etc), make sure you copy them to event 2 also, so particles keep moving when entering second event with changed color.

My next question would be... can the particles then be converted to VDBs and then colorized the same way? As I'm wanting to create that gaseous cloud effect where the particles change colors as the ship passes through it.