make the layer "IgnoreRaycast" work with collisions.

So, I'm making a script for building a "ShipPart" and I have to check if where I'm placing the object is a Valid spot to do this I use other object that I call BuildPreview.

On the BuildPreview objects I put the layer to IgnoreRaycast, because I need to go through the object with rays.

But at the same time this also causes the function OnTriggerEnter() to be never called. and if you're thinking "This guy probably forgot to check on isTrigger", no. I have isTrigger On

I need sone suggestion on how to make the collision work even if the object has the layer IgnoreRaycast.