Is there a way to explicitly check for collision?

I have gameObjects in my scene that need to be aware of whether they are colliding at startup (for inititalisation) with other gameObjects or not. Since they can´t have a rigidbody all the time I wanted to add a rigidbody to each gameObject in Start(), check whether they collide with something, store that information and remove the rigidbody again.

Now I wonder if there is a way to force a collision check for a gameObject at a specific place in code.

Anyone have a clue if that is possible?

Unfortunately this isn’t possible since Unity’s wrapper around PhysX is retardedly restrictive. Using Unity functionality you could approximate a collision check using raycasts or spherecasts. If you need accurate collision though you’ve no option but to implement your own collision detection routines.