How do I change an Object's Origin / Pivot Point >?

Hi, I only have the imported models, and their origins, rotation/transformation points are off the mesh. So when in game I instantiate them, they spawn off center.

Is there a way to move the origin point?

I have tried making an empty object and then making the other one a child with respect to that, it works for positioning but I have raycasting so it doesn't detect the mesh anymore....

I would really like to know if this can be done in unity since, the models that I get are rather small, so even if they were properly centered in their original 3D program, once I scale it up, it may screw up again.

Thanks in advance.

i believe you just position the model at the origin in the modeller. so after you're done modelling, set the position to 0,0,0 and export it to unity.

have you tried adding a collider to the empty object? - this wont be as accurate for collisions but is a possible solution