User Testing
Mechanism Design
Sustainability
SoleMates
A sustainable sneaker with a removable, replaceable outsole — its closure mechanism developed across two phases of prototyping and user testing for accessibility and ease of use.
SoleMates final prototype, on-foot
Role
Footwear & Mechanism Design
Timeline
1 Semester
Tools
Fusion 360, Sewing & Fabrication
Method
Iterative User Testing
The problem

The shoe industry produces 1.4% of global CO₂ emissions, and each shoe takes 30–40 years to decompose. SoleMates is a sustainable sneaker with a removable, replaceable outsole, built to cut that impact without giving up comfort, durability, or style. User research confirmed the core challenge: an upper that's durable, adjustable, and easy to clean — made sustainably.

Labeled diagram of the parts of a shoe upper
Fig. 1 — Parts of the shoe upper
Phase 1 — ideation & prototyping

Existing accessible mechanisms — zippers, velcro, elastic laces — often compromise aesthetics. Three concepts were sketched and built into modified sneakers for testing: a velcro opening replacing the laces for a wide slip-on, a ring twist that tightened loosely-tied laces by rotation (later swapped for a popsicle stick), and a drawstring threading four laces to a rear cord lock. User testing ranked all four mechanisms.

Sketch of velcro opening mechanism concept
Fig. 2 — Ideation: velcro opening
Sketch of drawstring mechanism concept
Fig. 3 — Ideation: drawstring mechanism
Velcro mechanism prototype worn on foot
Fig. 4 — Velcro mechanism prototype
Drawstring mechanism prototype worn on foot
Fig. 5 — Drawstring mechanism prototype
All final Phase 1 prototypes together
Fig. 6 — Final Phase 1 prototypes
User testing a Phase 1 prototype
Fig. 7 — User testing
“Users ranked the Drawstring design #1 for security and aesthetics — but the trailing laces posed a safety concern. The Ring Twist was #2. The solution: combine them.”
Phase 2 — from sketch to mechanism

Two hybrid concepts followed: a Loop mechanism pairing the drawstring with a clickable ring-twist, and a Knob mechanism feeding laces into a ratcheting spool turned by a palm-friendly knob — no fine motor skills required. Both were CAD-modeled in Fusion 360, 3D-printed, and tested on modified shoes. The Loop used tighter tolerances for a satisfying click-lock; the Knob used a ratchet spool with a quick-release button. Users strongly favored the Knob, leading to plans for a more compact, enclosed casing without the release button.

Sketch of the Loop mechanism concept
Fig. 8 — Loop mechanism — sketch
Sketch of the Knob mechanism concept
Fig. 9 — Knob mechanism — sketch
CAD model of the Loop mechanism
Fig. 10 — Loop mechanism — CAD
CAD model of the Knob mechanism
Fig. 11 — Knob mechanism — CAD
3D-printed Loop mechanism prototype on shoe
Fig. 12 — Loop mechanism — prototype
3D-printed Knob mechanism prototype on shoe
Fig. 13 — Knob mechanism — prototype
High fidelity — shoe construction

Cardboard lasts were built for a Men's Size 11, and a scaled-down pattern was traced onto canvas and a green sustainable fabric, cut, and sewn inside-out. Lace guides were stitched on, the tongue filled with cotton, and eyelets hammered in before the upper was shaped over the last and glued to the replaceable sole with contact cement. In parallel, the Knob mechanism went through several 3D-printed iterations — adding a spool casing, guide holes to stop lace tangling, and a more compact form that dropped the release button for reverse-turning instead.

Shoe pattern traced onto fabric
Fig. 14 — Pattern traced on fabric
Cardboard lasts wrapped in plastic
Fig. 15 — Cardboard lasts
Hand-sewn canvas upper before the sole was attached
Fig. 16 — Sewn upper, before the sole
Pair of shoes with eyelets and sole attached
Fig. 17 — Eyelets & sole attached
CAD render of knob mechanism, exploded gear view
CAD render of knob mechanism, assembled angle one
CAD render of knob mechanism, assembled angle two
Fig. 18 — CAD mechanism iterations
Who I worked with

SoleMates was a team project. I was involved across the full process — from mechanism ideation and CAD through construction and user testing.

Final product

The final SoleMates prototype combines a hand-sewn canvas-and-sustainable-fabric upper, a ratcheting knob mechanism at the heel, drawstring lacing guides, and a replaceable outsole connection system — delivering a shoe that is accessible, sustainable, and genuinely wearable.

Final SoleMates prototype, side view, worn on-foot
Fig. 19 — Final prototype — side view
Final SoleMates prototype, detail shot
Fig. 20 — Final prototype — detail
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