Ummm, but there’s still something I don’t understand. I get that I should first do the boolean thing and then apply the mirroring. This way the changes made by the boolean modifier applies to the other parts because the original part is mirrored in x and y. But then… why is it working in the X axis in my example? I mean, the boolean modifier has not being mirrored to the back (X axis), but it has been transferred to the left side (Y axis) as seen in the picture where all the front part has holes. Not just the original piece where I originally applied the booleans.
