Timeline and Feature Failure Recipes

Overview#

When a feature fails in Fusion, the timeline marks it, usually with a yellow warning or red error indicator, and downstream features may fail too. The cause is almost always geometric (the input no longer exists or is invalid), numerical (the operation cannot complete within tolerances), or logical (a parameter or reference is broken). This page is a recipe book: find the symptom, apply the fix. For the underlying theory of how the timeline works, see the Timeline and Timeline errors pages in Parametric Design.

Warning: Menu labels and message wording vary between versions. The recipes are described in terms of what the problem is rather than exact message text. Option names below were checked against the Model reference pages; items that could not be confirmed are marked "not confirmed".

Where to find it#

• Timeline: the bar at the bottom of the Design workspace. Items with yellow triangles are warnings; red markers are errors.
• Browser: failed items also show indicators beside sketches and components.
• Error messages: hover over the marked feature, or open the Edit dialog, which shows the error text.
• Timeline tools: double-click a feature, or right-click it and choose Edit Feature, Rename, Suppress Features or Create Group (Autodesk help: Use the Timeline). Playback buttons at the left of the timeline (Play, Move to Beginning, Move to End, Previous Step, Next Step) step through the history.
• Compute All: Modify > Compute All, or Ctrl+B (Command+B on macOS). Fusion normally computes automatically while you edit.
• Parameters: Modify > Change Parameters to check values that may have gone invalid.

The general triage method#

Follow this loop for any failure.

1. Find the first failure. Errors cascade. Fix the earliest failing item in the timeline order, because later ones often resolve themselves.
2. Read the message. It frequently names the cause: "reference missing", "self-intersection", "cannot create solid".
3. Roll back to just before the failure. Drag the timeline marker to the item before the failure so you can see the geometry at that moment.
4. Edit the failed feature. Double-click it; see which inputs are shown as missing (often highlighted or empty).
5. Reselect the inputs. Replace missing faces, edges, or profiles.
6. Try a simpler approach. If the operation will not compute, reduce the problem: smaller radius, fewer edges, different order.
7. Compute All. If everything looks right but errors persist, Modify > Compute All (Ctrl+B) recomputes all parameters, features and assembly relationships; a yellow warning or red error marks anything that still cannot compute.
8. Last resort: delete the feature and recreate it, or use direct edit tools for the specific change.

Recipes by symptom#

A feature turned yellow or red after I edited an earlier sketch#

Cause: the edit changed or removed geometry that later features reference (a face, edge, or profile).

Fix:

1. Roll back to the failed feature and edit it.
2. Reselect the missing face, edge, or profile.
3. If the sketch edit split or merged profiles, the original profile no longer exists. Select the new profile.
4. To avoid recurrence, constrain sketches fully and avoid referencing faces that sit on edited geometry. Prefer referencing origin planes and construction geometry.

"Reference missing" or the feature lost its input#

Cause: a sketch, face, or edge was deleted, or topology changed so the stored reference points to nothing. This is the topological naming problem that affects most parametric CAD.

Fix: edit the feature, reselect inputs, and in the future base features on stable references such as origin planes, construction planes, and user parameters rather than on faces that move.

Extrude has no profile or the profile will not select#

Cause: the sketch is not closed, curves overlap, a gap exists, or the profile is hidden by "Show profile" settings.

Fix:

1. Edit the sketch and look for gaps. Zoom in at endpoints; use Coincident constraints.
2. Check that no duplicate or stacked lines split a region into slivers.
3. Convert stray construction lines back or delete them.
4. Use the Sketch Palette's Show Profile and Show Points options to see open endpoints (see the Sketch Palette page in Sketching).
5. If the sketch crosses itself, trim the overlap.

Extrude cut or join produced nothing (or an unexpected result)#

Cause: wrong Operation (Join versus Cut versus New Body), direction, or extent. Also bodies may not intersect.

Fix: edit the feature, check the Operation dropdown, flip the Direction, set Extent to "To Object" or "All", and confirm the target body is selected in "Objects to Cut" (the Extrude option is named "Objects To Cut", available for cut operations; when you edit the operation you can recompute the bodies to cut with Auto-select or keep the original bodies).

Fillet fails#

Cause: radius too large for adjacent faces, tangent edge chains that collapse, tiny edges, or intersecting fillets.

Recipes:

• Reduce the radius until it succeeds and then increase gradually.
• Fillet in a different order. Large fillets first, small ones afterwards, or fillet with all edges in one feature to let Fusion resolve corners.
• Select the tangent chain rather than individual edges, or change the Corner Type: Rolling Ball combines rounded edges at the corner; Setback blends rounded corners into adjacent faces.
• Remove tiny sliver faces beforehand.
• For stubborn cases, try a Chamfer, use Press Pull on edges, or use a surface fillet and stitch.

Shell fails#

Cause: wall thickness exceeds a feature size, the offset self-intersects, or the face removed leaves an impossible geometry.

Recipes: shell earlier in the timeline, before fillets; shell outward instead of inward; decrease thickness; remove a different face; shell then fillet; use the direction options.

Loft fails or twists#

Cause: profiles with different numbers of segments, mismatched start points, or crossing rails.

Recipes: add the same number of segments to each profile, use the loft's connection points to realign, add centerlines or rails, set end conditions to Directional rather than Tangent, and loft in smaller steps.

Sweep fails or produces a twisted body#

Cause: path too tight, profile too large relative to curvature, or path not continuous.

Recipes: simplify the path, make it tangent-continuous, reduce profile size, set Orientation to Perpendicular or Parallel (Aligned is also offered for Solid Sweep), or use a Path + Guide Rail sweep. A "Frenet" orientation is not confirmed in Autodesk's documentation.

Combine fails ("bodies don't intersect" or the result is empty)#

Recipes: confirm overlap, move bodies slightly, use Keep Tools, check for coincident faces which cause numerical failures, offset one body by a very small amount, or use Boundary Fill.

Hole or thread fails#

Cause: the target face is not planar or has insufficient depth, or the threads exceed the model length.

Recipes: use Placement options rather than sketch point selection, use a flat pre-feature, use cosmetic threads, or change thread class and size.

Mirror or pattern fails#

Recipes: change the Compute Type (Optimized is fastest, Identical replicates the original features' results, Adjust calculates each instance individually and is slowest; available when Object Type is Features), reduce the number of copies, check that the pattern references still exist, pattern bodies instead of features when features depend on nonexistent faces, or switch to "Faces" patterning.

Joint fails or components jump#

Cause: joint origins reference geometry that moved; components are grounded incorrectly; or conflicting joints over-constrain the assembly.

Recipes: open the joint and reselect the origin; temporarily remove a joint to test; ground only one component; use As-built joints for existing positions; check Joint Limits. See the joints pages in section 05.

Parameter or expression errors#

Cause: a parameter was renamed or deleted, a unit mismatch exists (mixing length and angle), or a circular dependency appears.

Recipes: open Change Parameters; inspect any red entries; fix unit issues (for example, 10 mm versus 10 deg); break circular references; see the units and expressions pages in Parametric Design.

Sketch has over-constrained or conflicting constraints#

Recipes: read the warning; use the Sketch Palette to remove Constraints; delete the last dimension you added; convert redundant dimensions to Driven; undo and apply constraints in a different order. See the Sketching troubleshooting page.

"Sketch is not on a plane" or the sketch moved#

Cause: the sketch plane was a face that changed or vanished.

Recipe: edit the sketch plane (Autodesk has a "Redefine a sketch plane" topic in the Sketch help; the exact menu path is not given in the mirror) and attach it to a stable plane.

Derived or linked component is stale or broken#

Recipes: open the source design; update the reference; if the source moved, re-establish via Insert; break the link only if you accept the loss of updates.

The timeline is slow or computing endlessly#

Recipes: edit a later item rather than an early one; remove unneeded patterns; see the Performance page in this section.

Everything is red#

Recipes: find the first red item (earliest). Roll the marker before it. Often one sketch or imported body is the root. Delete or fix it and the rest recompute. If an imported mesh or an externally referenced file broke, that is usually the root cause.

Prevention habits#

Options reference#

Tips and pitfalls#

Tip: Hold your cursor over the yellow or red icon. The tooltip frequently states the reason in one line.

Warning: Inserting features while the marker is rolled back places them mid-timeline. This is powerful but can break later features. Return the marker to the end before continuing normal work unless you intend the insertion.

Warning: Deleting a feature to fix an error may cascade. Use Undo immediately if the result looks worse.

Tip: If a fix is unclear, duplicate the design (Save As), and try the aggressive fix in the copy.

Practice exercise#

1. Create a block, fillet its top edges, and shell it. Then edit the block's width to a very small value until the fillet fails.
2. Observe the error. Reduce the radius, then re-enlarge the width.
3. Delete a sketch that a feature uses; observe the failure; re-create the sketch and repair the feature.
4. Reorder: move the shell before the fillet (drag the feature) and see whether the model behaves better.

Expected result: you recognize the typical failure signatures and can restore a working timeline within minutes.

Related#

• Timeline errors (Parametric Design)
• The timeline (Parametric Design)
• Rollback and editing features (Parametric Design)
• Sketching troubleshooting (Sketching)
• Crashes, bugs, and cache clearing (this section)