Is a ʼProjected Geometryʼ linked to the original object in Autodesk Fusion?
Short Answer
Yes. In Autodesk Fusion, geometry created with Project is usually linked to the original object by default, so the projected sketch updates when the source geometry changes. This is the most common professional workflow for stable parametric sketches. Limitation: the link can break if the source face, edge, or body is removed or replaced.
What You Need to Know Before
Warning: projected geometry in Fusion is not just copied lines; it often carries a live parametric reference to the original edge or face. A common hidden failure is timeline edits that change topology, which can cause lost references or yellow/red sketch warnings later.
How to Keep Projected Geometry Linked
Command: Project
Shortcut: P
Quick Steps:
- Edit the target sketch, then go to Sketch > Create > Project/Include > Project in the Ribbon.
- Select the edges, faces, or sketch geometry you want to reference in the sketch.
- Make sure the Projection Link option is enabled, then click OK to create linked projected geometry.
Variables & Settings
Key Setting: Projection Link toggle
Expert Setting: When Projection Link is turned on, the projected sketch entities stay associated with the source geometry and update parametrically. If turned off, Fusion creates unlinked reference geometry that will not update when the original object changes.
Why it Fails
Cause 1 (Geometry): the original edge or face changed identity after a feature edit, fillet, split, or rebuild, so the projected reference can no longer resolve correctly.
Cause 2 (layers/Locks): the sketch may be constrained or partially locked by existing dimensions and constraints, preventing expected edits even though the projected geometry updates.
Cause 3 (Command/Logic): Projection Link was disabled during projection, so the result is static sketch geometry instead of a live reference.
Quick Fix & Best Practice
Quick Fix: Edit the sketch, delete the broken projected entities, then rerun Project with Projection Link enabled.
Manager’s Verdict: Use linked projected geometry for production parametric models, especially for layout-driven sketches. Avoid over-projecting unstable edges from heavily edited faces; reference simpler master geometry when possible.
FAQ
Does projected geometry update automatically in Fusion?
Yes, if it was created with Projection Link enabled.
Can I break the link on projected geometry?
Yes, by projecting with Projection Link turned off or by recreating the geometry as independent sketch entities.
Why is my projected sketch geometry purple?
Because Fusion displays projected reference geometry in purple to show it is linked or externally referenced.
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