"Practice ALL Fusion Sketch Constraints | Day 14 of Learn Autodesk Fusion in 30 Days (2026 EDITION)" — Product Design Online

Why this is in the vault

Series continuity. This is Day 14 of the 30-day Fusion course already tracked in the vault (Days 12 and 13 filed). It is a hands-on drill that names and demonstrates all 13 Fusion sketch constraints in one sitting — the closest thing the course has to a reference card. Filed as design-skill craft material on the digital-manufacturing learning track. The RDCO mapping is honestly weak (see below); this clears the vault bar on series-completeness and as a one-stop constraint glossary, not on strategic relevance.

Episode summary

Kennedy builds a household electrical receptacle (outlet) cover sketch from scratch and uses it to walk through every sketch constraint Fusion offers. He starts with a deliberately crooked, under-defined rectangle and progressively tames it: coincident to glue points and pin the sketch to the origin; parallel, perpendicular, and horizontal/vertical to true up the edges (triggering an intentional "over-constrained" error to explain the concept); equal and midpoint on circles; construction lines as references; symmetry to mirror the two outlet cutouts about a center axis; concentric for shared centers; tangent on three-point arcs for the rounded ends. He then fully defines the sketch with six dimensions (4 mm screw hole, 17 mm arc radius, 115 mm height, 80 mm width, 28 mm cutout height, 6 mm offset) so geometry turns from blue to black. He closes by covering the four less-common constraints — fix/unfix, collinear, curvature (G2), and the new March 2026 polygon constraint — then sets a challenge (fully constrain the Fusion logo) and previews Day 15 (a customizable painter's pyramid).

Key arguments / segments

[00:00:09] Hook and intro: change one dimension and an under-defined design twists into chaos. The biggest beginner mistake is skipping constraints to save time, which costs hours later fixing cascading broken geometry. Constraints make models stable, fast, and predictable.
[00:01:01] Setup: new part-design file, save, then start a sketch on the XY origin plane with the line tool. Pro tip — double-click to end a continuous line segment while keeping the line tool active. Delete any auto-applied constraints to start clean.
[00:02:01] Coincident (most-used): snaps two points, or a point to a line, together. Used to pin the sketch's bottom-right corner to the origin so the whole sketch is glued in place permanently unless the constraint is deleted.
[00:03:01] Parallel, perpendicular, and horizontal/vertical applied to the crooked rectangle. Horizontal/vertical snaps a line to whichever axis it sits closer to.
[00:04:02] Over-constrained demonstration: selecting the top line for vertical/horizontal after a corner is already perpendicular throws an error. Over-constrained = adding a constraint or dimension that contradicts an existing one; Fusion blocks it because it cannot solve two conflicting equations.
[00:04:30] Equal (two circles forced identical) and the rule that deleting a sketch object also deletes its associated constraints.
[00:05:00] Midpoint requires a line to reference; a diagonal construction line is drawn corner-to-corner, then the circle center snaps to its midpoint (triangle glyph). Construction geometry positions things without affecting the sketch profile or 3D features.
[00:06:00] Two-point rectangles for the outlet cutouts auto-pick up horizontal/vertical constraints. Pro tip — hold Cmd (Mac) / Ctrl (Windows) to suppress automatic snapping and constraints when they get in the way.
[00:07:01] Symmetry: select the two objects, then the symmetry (construction) line, repeated for all four sides to mirror the two cutouts. Warning — use symmetry sparingly; it causes sketch latency. Prefer mirroring or patterning solid features instead.
[00:10:01] Heuristic — many constraint combinations reach the same result; pick the one using the fewest constraints / least construction geometry. Bake "design intent" in so edits propagate as intended. Then three-point arcs round the cutout ends, with the tangent glyph/constraint explained (smooth transitions, matters most for lofts).
[00:12:00] Concentric (shared center for arcs/circles/ellipses), the sketch-palette settings to hide construction geometry/constraints/dimensions, and re-parenting the sketch by deleting the corner coincident and re-applying coincident center-to-origin.
[00:14:00] Fully define with six dimensions (4 mm hole, 17 mm arc radius, 115 mm height, 80 mm width, 28 mm cutout, 6 mm offset). Geometry turns blue → black = fully defined; now the cover scales predictably.
[00:15:02] The remaining four: fix/unfix (locks geometry green; good for imported DXF/SVG or complex splines), collinear (objects share a common line/direction), curvature (G2-continuous, vs tangent's G1; for surface/loft work), and the new March-2026 polygon constraint (forces a closed profile to stay a regular polygon).
[00:17:24] Challenge (fully constrain the Fusion logo) and Day 15 preview (painter's pyramid). Outro card promotes Kennedy's paid PDF guide bundle.

Notable claims

There are 13 sketch constraints in Fusion; the most-used is coincident, the second most-used is horizontal/vertical.
"Over-constrained" specifically means adding a constraint/dimension that contradicts an existing one — Fusion refuses it rather than silently producing broken geometry.
The symmetry constraint is real but performance-costly; the recommended pattern is to use it lightly in sketches and instead mirror/pattern at the solid-feature level.
Tangent yields G1 (slope) continuity; curvature yields G2 (curvature) continuity — relevant for surface modeling and lofts.
The polygon constraint is a recent addition (Autodesk, March 2026); rarely needed because Fusion already has preset polygon sketch tools.
A fully defined sketch displays black geometry (under-defined is blue); fix/unfix-locked geometry displays green.

Guests

Solo instructor — Kevin Kennedy (channel owner, Product Design Online). No guests.

Sponsorship

No third-party sponsor. House-promo only: the video description and the outro card push Kennedy's own paid "Learn Autodesk Fusion in 30 Days" PDF guide bundle (Part 1: Days 1-15) plus a free downloadable challenge sheet and Fusion file. sponsored: true is set to flag the self-promotion; treat the instructional content as unbiased — there is no external advertiser shaping it.

Mapping against Ray Data Co

Weak, and honestly thinner than even the Day 13 note's mapping. This is a pure tool-mechanics drill (which button does which constraint), not a conceptual lesson. The one transferable thread is the same one already captured for Day 13 and worth less on repetition: a fully constrained/defined system changes predictably, while an under-defined one cascades into breakage on a single edit — the same robustness instinct behind data contracts, typed schemas, and parametric derivations over snapshot values. There is no Squarely, RDCO-strategy, or founder home-rebuild-2027 hook beyond generic 3D/CAD literacy. Filing rationale is series-completeness and constraint-reference convenience, not strategy. A skip-stub would have been defensible; it is retained because the course is being tracked end-to-end and this episode is its single best constraint glossary.

[[2026-05-30-product-design-online-fusion-day-13-construction-planes]]
[[2026-05-15-product-design-online-fusion-day-12-screwdriver]]
[[2026-06-03-product-design-online-fusion-ai-update]]

product design online practice all fusion sketch constraints