Model → Test → Refine
Use drawings, physical prototypes and CAD models as instruments for gathering evidence—not as display pieces.
By the end of class, you should be able to…
Choose the right model
Match the representation to the design question.
Gather evidence
Distinguish measurable data from user/client feedback.
Analyse results
Turn evidence into a design judgement.
Refine iteratively
Make a targeted change and test again.
A prototype is a question you can interact with.
The best prototype is not always the most realistic one. It is the one that helps answer the next important uncertainty.
Drawing
Best for proportions, component relationships, dimensions, assembly communication and quick feedback.
Physical prototype
Best for touch, reach, grip, space, motion, fit, perceived comfort and real-world interaction.
CAD model
Best for geometry, variants, interference, visualization, rapid-prototyping preparation and some forms of simulation.
Measured / observed
Interpreted by people
Model
Represent the uncertain feature.
Test
Use a planned method with users/clients or measurements.
Analyse
What does the evidence mean?
Refine
Change the feature for a reason.
Retest
Check whether the change improved the result.
Example: lid opening force
Can the intended user open the lid with one hand without excessive force?
Test three hinge geometries with the same user task and record success/errors + user confidence.
Keep a geometry only if the user completes the task reliably and rates control as acceptable.
Change hinge leverage / grip area—not random aesthetics.
You need to test whether a handle is comfortable during a 30-second carrying task.
Do not ask only “Do you like it?”
Observe behaviour
Where do they hesitate? Re-grip? Make errors? Compensate? Ignore a feature?
Ask targeted questions
What felt difficult? Which option gave more control? What would stop you using it?
Keep task/context realistic
A prototype tested in an unrealistic task can produce misleading evidence.
Record the result
Photos, measurements, short quotes, tables and annotated changes can make iteration visible.
Prototype theatre
Building something impressive that answers no defined design question.
Confirmation bias
Testing only to prove the idea works rather than discover weaknesses.
Uncontrolled comparison
Changing many variables at once, so the cause of improvement is unclear.
No retest
Making a refinement but never checking whether it actually helped.
Can you explain the chain without notes?
Use this loop to decide between your top concepts.
Criterion C asks you to evaluate redesign ideas against the design specifications through testing and user feedback.
Before you leave…
IA Day 10 — Evaluate Concepts with Users & Specifications
Keep the evidence chain moving: user → research → decision → test.
B2.2.6: prototypes gather data and feedback from potential users and clients; select and use appropriate drawings, physical prototypes and CAD models to gather relevant data and feedback, then analyse and develop the design iteratively.