How to detect collision without reaction (Panda3d + ODE)?

The functionality you’re looking for is generally referred to as “Area Trigger”. I’ve implemented that in my ODE middleware.

[ODE Middleware) <= you can check it out here.

On a side note, it’s done by not using Panda’s auto collide. I handle the collisions in my own code there because I found not satisfying way of making area triggers with auto collide. So the API is somewhat different than the standard Panda-ODE.