The mirror modifier isn't projecting the object in the place I want it. What am I doing wrong, and what can I do to fix it?

Question

The imagine below shows where the object is being mirrored, it should be on the other side of the UV sphere though. Any way I can fix this???

Answer 1

The mirror modifier doesn't work as you first might think of. But if you once understand how it works, it is working pretty logically.

First the basics:

Every object in Blender has an origin (or pivot) point. This point can be anywhere. It doesn't have to be "inside" the object (mesh).

You can see the origin point if you check "origins" here:

Example: origin outside of the object

Example: origin inside of the object

Why is the origin so important?

Because a lot of calculations depend on that point, like rotation as you can see here:

So the pivot point is the center of the rotation.

You can e.g. change the pivot point (relative to your mesh) by going in edit mode with "TAB" and then moving the mesh (this just moves the mesh, not the pivot point, but of course this will change the rotation behaviour of it) or you click on "options" and check "origins".

If you select an object and press G you will only move the origin point.

The mirror modifier does exactly the same as the rotation: it takes the pivot point as "mirror position" (as long as you don't choose a mirror object - then of course that point will be the mirror position).

So here is the result:

If your object is rotated before using the mirror modifier, this will also taken into account. So you have to apply the rotation before using it so it looks more "logically" how the mirror modifier should work (although the result is still right without applying).