Actually, it works very well, but mirroring something is not quite as apparent as we might expect. Why the Blender programmers don’t make it as easy to use as CAD programmers do is a mystery to me. But… what do I know? I’m not a programmer.
Consider this simple object. It’s just a cube with two edges bevelled so we can easily see what is happening. The object origin is located at the world origin; the cursor is located at the object origin. So it can hardly get more straightforward than that :
Now let’s mirror it so that the filleted edges are mirrored to the other side. Select the object and add a mirror modifier.
Ok, let’s push some buttons on that modifier…
And then the object seems to turn into a cube!
Well, let’s see if turning on transparent mode and Wireframe mode helps clarify matters…
The object is indeed being mirrored across the Y-axis. Still, because the Y-axis (The red line in the image) runs right through the middle of the object – it is actually mirroring about itself.
So how do we Fix this Mirror?
This is the point where Blender becomes non-intuitive but is quite logical if you think about it.
Switch to edit mode and select the image:
So now we move the selected edges away from the red X axis in the Y Direction (The green axis).
If we want them to join one another “back to back”, we simply move them back in the Y direction until they meet:
If you check the Clipping box in the Mirror modifier panel after you have brought them together, this acts as a sort of glue.
Now if you move the selection outward again, it stays glued together and simply extrudes the joining faces:
To finish off, toggle to object mode and apply the modifier:
This is the simplest way to mirror an object, but there are some problems with this method that may or may not affect you.
- The first problem is that you are physically moving the object you already made. This may or may not be a problem to move the original object back to where it was.
- If you are trying to model precisely, the two flat faces may not perfectly coincide without some fiddling.
- There will be an internal face created after applying the modifier.
- If you want to mirror across a plane that is not parallel to an axis, the mirror gets very difficult to construct.