New houdini beginner here. I wanna do this, Particles hit black surface die, hit white surface bounce. any ideas?

If your collisions are handled by a popsolver, there are options in the Collision Behavior tab of the popsolver, to add prim and UV attributes on hit.
With those attributes you can sample any attrib from the hit surface using primuv function in VEX: https://www.sidefx.com/docs/houdini/vex/functions/primuv.html [www.sidefx.com]

play_w_madness
If your collisions are handled by a popsolver, there are options in the Collision Behavior tab of the popsolver, to add prim and UV attributes on hit.
With those attributes you can sample any attrib from the hit surface using primuv function in VEX: https://www.sidefx.com/docs/houdini/vex/functions/primuv.html [www.sidefx.com]

Hi, play_w_madness, Thank you for reply. Another problem here, How to detech which geo particles hit? I wanna group particles based on specific geo particles collide with.