Craftwork
Senior 3 · Fine Arts
Craftwork
Lesson 4 of 4
25 min
Professional designers expect their first model to go wrong, which is why they make it quickly, from cheap materials, before they cut anything precious. A paper model that tears in a test costs nothing; a finished bag that tears in a market costs a customer. In this lesson you will turn your plan from Lesson 2 into a prototype, test it against your specification, improve it through several versions, and finish it to a standard you would be proud to sell or give.
Definition
Mock-up: a quick model, often in paper or card, used to check size, shape and proportion.
Prototype: a working version made in the real or similar materials, used to test whether the design functions.
Iteration: one round of making, testing and improving; each round produces a new version.
User feedback: comments from the people the object is designed for, gathered while they try it.
Evaluation: judging the finished object against the specification, with evidence from tests.
| Specification point | Fair test | Result (illustrative) | Pass? |
|---|---|---|---|
| Holds at least 1 kg | fill with exercise books on a kitchen scale; hang for one day | held 1.5 kg; no tearing | yes |
| Does not sag | measure the bottom pocket's depth before and after loading | sagged 4 cm (version 2); 0.5 cm (version 3) | yes, in v3 |
| No sharp edges | run a cloth over every edge: does it catch? | no catches after binding | yes |
| At least 80% reused waste by mass | weigh the reused parts and the whole object | see Worked example 1 | yes |
Keep a refinement log in your design folder: for each version, write what you changed, why, and what the test showed. Photograph every version. This record shows your thinking and is assessed as well as the final object.
Write a short evaluation: which specification points it meets, with evidence; what users said; what you would change in a next version; how it could be repaired; and how much waste it saved from being thrown away. Present the object with your design folder: brief, specification, ideas, drawings, refinement log and evaluation.
Worked example 1: how much of it is waste?
Uwera's finished storage pocket weighs 400 g. The only new materials are thread, glue and binding tape, which together weigh 40 g. What percentage of the object is reused waste, and does it meet the specification of at least 80%?
Reused mass: .
Percentage: .
Conclusion: 90% is more than 80%, so it meets the specification.
Worked example 2: is it worth making?
The new materials for one storage pocket cost about Frw 500. A similar bought organiser costs about Frw 3,000 (illustrative prices). How much does the maker save, and what else should the evaluation consider?
Saving: , so about Frw 2,500 per piece.
Also consider: the time taken to make it, how long it will last compared with the bought one, and the waste kept out of the environment. A fair evaluation weighs all of these, not only the price.
<em>Cardboard modelling</em>, from the James Dyson Foundation. Watch how quick card models are used to test ideas before anything is made properly, and note one technique you could use for your own mock-up.
Warning
Changing everything at once. If you change three things between versions, you will not know which one fixed the problem. Change one thing, then test.
Tools. Use files, snips, punches and needles carefully, store them safely, and report any cut at once.
Tip
Make it fast, test it fair, change one thing. Then record it in your refinement log.
Practice
What is the difference between a mock-up and a prototype?
Why should you change only one thing between versions?
A recycled bag weighs 600 g, of which 90 g are new materials. What percentage is reused waste?
Describe a fair test for the specification point "the toy car rolls at least 1 m when pushed gently".
Write two questions you would ask a user who is trying your prototype.
Evaluate this report: "Version 3 is much better. Everyone liked it." What is missing, and how should it be improved?
Making task. Build a mock-up and at least two prototypes of your object, test each against your specification, keep a refinement log, then finish the final version and write its evaluation.
1. A mock-up is a quick model, often paper or card, to check size and shape; a prototype is a working version in real or similar materials, used to test function.
2. So you know which change caused the improvement (or the problem).
3. .
4. For example: release the car from the same small ramp each time, on the same floor, three times; measure the distance with a tape measure and take the average.
5. For example: "What was easy or difficult when you used it?" "What one thing would you change?"
6. It gives no evidence. It should say which specification points were tested, give the results with numbers, compare them with version 2, and report specific user comments.
7. Check: mock-up and two or more prototypes photographed; tests recorded against the specification; refinement log; finished object; evaluation with evidence.
Look back at your first idea in Lesson 2 and your final object. What is the most important thing that testing taught you that you could not have known at the start?
Further reading
Sources and credits
