Help how to remove fixed state

[Richard]

the particle index runs from 0 (first particle in the actor) to the number of particles in the actor. So depending on which particle you want to fix/unfix, you have to use a different index. How to get it depends on what you need to do at runtime: do you pick particles with mouse, or in response to a collision? do you simply want to unfix all fixed particles?

The inverse mass is, as the name implies, 1/mass of the particle. So high inverse masses will cause the particle to be lighter. Low values will make it progressively heavier, until you reach 0 and the particle is infinitely heavy (fixed).

I would like to unfix all fixed particles.