Collision detect objects "behind" me

Questions
1

Hi,

I have an array of objects (planes) which I detect if the camera intersects with.

this.colliders = [  plane01, plane02 ... plane20 ];

const intersects = this.raycaster.intersectObjects( this.colliders, false);

if (intersects.length > 0) {
if (intersects[0].distance < this.controls.target.distanceTo(this.camera.position)) {
    //good enough reliable collision detected here
}
}

Now the problem - as long as all planes/objects which needs to be collision-detected are in the “view”/in front of my camera → all working as expected.

Now I want to detect whether an object is behind the camera and if it would be possible to move the camera a few steps backwards without colliding. Can I somehow detect/raycast objects which are not within camera´s direction/view?

Thanks
b

2

And according to that problem - how can I make an object look always to the “counter-direction” of the camera?

Say_ camera is y.rotation in degrees is 45° - i want one object look exactly in the counter-direction and so on …