Mirror mode lets you create symmetrical geometry without drawing the same shape twice

Mirror in Fusion 360 is a tool that flips a sketch or body across a plane, creating a mirrored copy on the other side. Instead of drawing both sides of a symmetrical part, you draw one side, then use Mirror to duplicate it in reverse. The mirrored geometry stays linked to the original — if you change one side, the other updates automatically.

You can mirror sketches while you are still drawing them, or mirror finished bodies after you have completed the design. The steps differ slightly depending on which you are mirroring, but both are straightforward once you know where the tool lives.

Key Takeaways

  • Mirror in the sketch workspace is found in the Sketch menu, and you select the geometry you want to mirror before clicking the tool.
  • Mirror for finished bodies lives in the Design workspace under the Modify menu, and you choose the plane the geometry mirrors across.
  • Mirrored geometry stays linked to the original, so edits to one side automatically update the other side.
  • You must have a plane to mirror across — this is usually the center plane of your part, but can be any flat plane in your design.
  • Mirror works on sketches, bodies, and features, so you can use it at almost any stage of your design process.

Mirror a sketch while drawing

If you are still working inside a sketch and want to mirror the geometry you have drawn, select the lines, circles, or other shapes you want to copy. Click on the sketch geometry with your mouse to highlight it — you can select multiple objects by holding Ctrl (or Cmd on Mac) and clicking each one.

Once your geometry is selected, open the Sketch menu at the top of the screen. Look for Mirror in the dropdown list. Click it. A dialog box will appear asking you to choose a mirror line — this is the line your geometry will flip across. Click on a line in your sketch that represents the center, or click on a construction line you have already drawn for this purpose. Fusion 360 will create a mirrored copy on the opposite side of that line.

The mirrored sketch geometry is now part of your sketch. You can continue editing, and any changes you make to the original geometry will update the mirrored side automatically. When you finish the sketch and extrude or otherwise turn it into a 3D body, both the original and mirrored sides will become part of the solid.

Mirror a finished body or feature

If you have already created a body or feature and want to mirror it, you work in the Design workspace instead of the sketch workspace. Right-click on the body or feature you want to mirror in the browser panel on the left side of your screen. A context menu will appear. Select Mirror from the list.

A dialog box will open. It will ask you to choose a Mirror Plane — the flat plane that your body will flip across. In most cases, you will see the center plane of your part listed as an option. Click on it to select it. If you do not see a suitable plane, you can create one by clicking Create New Plane in the dialog, though this is less common for basic mirroring.

Once you have chosen the plane, click OK. Fusion 360 will create a mirrored copy of your body on the opposite side of the plane. The original and mirrored bodies are now linked — if you edit the original, the mirror updates to match.

Choose the right mirror plane

The mirror plane is the invisible line down the middle that your geometry flips across. For most parts, this is the XY plane, YZ plane, or XZ plane — Fusion 360 creates these automatically when you start a new design. You can see them listed in the browser panel on the left under the component name.

If your part is symmetrical left-to-right, mirror across the YZ plane. If it is symmetrical front-to-back, mirror across the XZ plane. If it is symmetrical top-to-bottom, mirror across the XY plane. The plane you choose depends on which direction your symmetry runs.

You can also create a custom mirror plane if the default ones do not work for your design. In the Design workspace, go to the Construct menu and select Create Plane. Define the plane by clicking on edges or faces of your part, then use that new plane as your mirror plane. This is useful for parts with unusual symmetry.

What happens when you mirror a sketch versus a body

Mirroring a sketch creates mirrored lines and shapes within the same sketch. Both the original and mirrored geometry live in one sketch file, and they stay linked. If you change a dimension on one side, the other side updates automatically. This is the fastest way to design symmetrical parts because you only draw half of it.

Mirroring a body or feature creates a separate mirrored body in your design. The original body and the mirrored body are linked through the Mirror feature, but they are technically two separate objects in your browser. You can edit them independently if you need to, though changes to the original will still update the mirror by default.

Choose sketch mirroring if you are still designing and want everything in one sketch. Choose body mirroring if you have finished one half of your part and want to quickly create the other half without redrawing.

Editing or removing a mirror

If you need to change which plane your geometry mirrors across, right-click on the Mirror feature in the browser panel and select Edit. The dialog box will reopen, and you can choose a different mirror plane. Click OK when you are done.

If you want to remove the mirror and keep only the original geometry, right-click the Mirror feature and select Delete. The mirrored copy will disappear, but your original geometry stays intact. If you delete a mirror and later want it back, you can undo the deletion by pressing Ctrl+Z (or Cmd+Z on Mac) immediately after.

You can also suppress a mirror temporarily without deleting it. Right-click the Mirror feature and select Suppress. The mirrored geometry will hide, but the mirror feature remains in your browser so you can turn it back on later by selecting Unsuppress.

Common mistakes and how to avoid them

The most common mistake is forgetting to select your geometry before clicking Mirror in the sketch workspace. If you click Mirror and nothing is selected, Fusion 360 will ask you to choose what to mirror. Select your geometry first, then open the Mirror tool — this is faster and less confusing.

Another mistake is choosing the wrong mirror plane. If your mirrored geometry appears on the wrong side or in the wrong direction, you chose the wrong plane. Edit the mirror, select a different plane, and try again. There are only three default planes, so you can test each one quickly.

A third mistake is mirroring a body that is not centered on the mirror plane. If your original body is off to one side, the mirrored copy will be off to the opposite side, and the two will not line up. Make sure your original geometry is positioned so that the mirror plane runs through the center of your symmetry before you create the mirror.

Frequently Asked Questions

Can I mirror a sketch that has constraints?

Yes. Constraints on the original geometry will apply to the mirrored geometry as well. If you have set a dimension on one side, the mirrored side will have the same dimension. This is one reason sketch mirroring is so useful — you only have to constrain half your sketch.

What if I mirror a body and then want to edit just one side?

You can edit the original body, and the mirror will update automatically. If you want to change only the mirrored side without affecting the original, right-click the Mirror feature and select Break Link. This breaks the connection between the two, and you can edit them independently from that point forward.

Can I mirror multiple bodies at once?

No. You must mirror one body or feature at a time. If you have several bodies you want to mirrored, create a Mirror feature for each one. You can speed this up by copying and pasting the Mirror feature if the bodies use the same mirror plane.

Does mirror work on imported geometry?

Mirror works on bodies you have created in Fusion 360. If you have imported a part from another program, you may need to convert it to a native Fusion 360 body first. Right-click the imported body and select Convert to Body, then you can mirror it normally.

What if my part is not perfectly symmetrical?

Mirror creates an exact copy in reverse. If your part should not be perfectly symmetrical, do not use Mirror. Instead, draw both sides separately or use Mirror and then edit one side after the fact. You can break the link between the original and mirrored geometry if you need them to be different.