Is a ʼMirrorʼ feature updated if the original part changes in Autodesk Fusion?
Short Answer
Yes. In Autodesk Fusion, a mirrored feature usually updates when the original part changes if you created it with the timeline-based Mirror command using the standard parametric workflow. The mirror stays associative to the source feature, body, or face selection. Limitation: it can fail if references break after major geometry edits.
What You Need to Know Before
Warning: Mirror updates depend on stable references in the design timeline. If you mirror faces instead of features or bodies, later edits such as deleted faces, split bodies, or topology changes can break the mirrored result unexpectedly.
How to…
Command: Mirror
Shortcut: No default keyboard shortcut
Quick Steps:
- In the Design workspace, go to the Solid tab > Create panel > Mirror.
- In the dialog, set Pattern Type to Features for the most reliable professional method, then select the source feature from the timeline or model.
- Select a plane or planar face as the Mirror Plane, confirm Compute Option if shown, then click OK.
Variables & Settings
Key Setting: Pattern Type
Use Features when possible because it preserves parametric intent better than mirroring faces. Bodies is also reliable for solid duplication, while Faces is more fragile and more likely to fail after upstream edits.
Why it Fails
- Cause 1 (Geometry): The original feature changes enough that mirrored faces or edges no longer exist in the same form, causing lost references.
- Cause 2 (layers/Locks): The mirror plane or source geometry may come from a hidden component, suppressed feature, or inactive component context, which can disrupt updates.
- Cause 3 (Command/Logic): The mirror was created as a non-ideal type, such as mirrored faces instead of mirrored features, or outside the intended parametric timeline workflow.
Quick Fix & Best Practice
- Quick Fix: Edit the Mirror feature in the timeline, reselect the source using Pattern Type = Features or Bodies, and reassign the mirror plane if references are broken.
- Manager’s Verdict: Use mirrored features for symmetric design intent and mirrored bodies for robust solid duplication. Avoid mirroring faces for production models unless the geometry is very stable.
FAQ
Does a mirrored body update automatically in Fusion?
Yes, if the mirror is timeline-based and the source body still exists.
Is mirroring features better than mirroring faces?
Yes, mirrored features are usually more stable and easier to maintain.
Can I mirror across a construction plane?
Yes, a construction plane is a standard and recommended mirror plane in Autodesk Fusion.
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