How to check collision with paused simulation

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Hi I'm doing some Reinforcement Learning so at every episode I reset the simulation and set the robot joints in a random configuration. So I need to check that the random joints position are collision free.

For collision check I use a set of bumpers, although since the simulation every time is reset paused (simulation has to start paused, it is a long story) the bumpers obviously do not work. Is there a gazebo plugin that allows to check collisions while simulation is paused?

P.S. the problem is only at the beginning of the simulation