Concept brainstorming, bounded.
Also called: Concept generation · Solution ideation · Form-factor exploration · Design concepting
Generating several concrete ways to build the chosen product, then screening each one against the fixed brief, spec and manufacturing reality.
The brief and spec are locked, so now you invent how the thing is physically built: form factors, mechanisms, layouts. Generate several, then screen each against brief, spec and cost together. A concept that wins on one and fails another is not a concept yet.
What concept brainstorming is
This is not the idea brainstorm from Stage 02. That session asked “what should we make?” and produced the proofing box. Concept brainstorming asks the next question: how do we actually build it? The product is fixed; the engineering form is wide open. You are generating physical arrangements, shapes, mechanisms and layouts that could each deliver the same agreed result.
The discipline that separates this from daydreaming is that every concept lives inside three walls at once. The brief says what the user must get. The spec says the measurable targets the design must hit. The manufacturing reality says what a Stoke-on-Trent pottery and a Manchester PCB house can actually make at the cost you can afford. A concept is only real if it can satisfy all three together, not one at a time.
Why people generate badly here
- They stop at the first concept that excites them. The lidded crock looked beautiful in a sketch, and the team nearly stopped there. A single concept is not a choice; it is an attachment.
- They ignore one wall. A concept that nails the brief but can’t hold ±0.5°C, or holds it but costs £90 to build, has quietly failed a wall and nobody noticed.
- They concept in the abstract. “A smart heated box” is not a concept. A drawer that pulls out, a dome that lifts off, a double wall that insulates: those are concepts, because you can screen them.
The candidate concepts, screened
For the proofing box we worked up four genuinely different forms before picking one. Here is the screen we ran, so you can see the shape of a good answer rather than a generic template. Each concept gets one honest line against brief, spec and cost together.
Notice the winner is not the prettiest concept; it is the one that survived all three walls at once. The crock and the cloche each won on one wall and lost on another, which in this work means they lost.
- Sketches the lidded crock, loves it, and stops.
- Defends the look when the spec says it sheds heat.
- Never finds out the double wall existed.
- Generates four genuinely different forms.
- Screens each against brief, spec and cost together.
- Picks the one that passes all three, on evidence.
How it fits the bigger picture
Concept brainstorming is activity 06.10.01, the first activity of Stage 06 Design. It takes the locked brief and specification from Stage 05 Define and turns them into candidate forms. The concept that survives the screen then feeds straight into sketch ideas (06.10.02), where the chosen form is drawn up properly before any CAD.
What it can do
It forces the team to invent more than one way to build the product, and to judge each one against the brief, the spec and the factory floor at the same time. That is how a beautiful concept that can’t hold temperature gets caught at the sketch stage instead of at tooling.
What it can’t do
It can’t prove the chosen concept actually works; that is what sketch ideas, CAD and prototyping do downstream. The screen here is a reasoned shortlist on paper, not a test. A concept that passes all three walls on the table can still surprise you on the bench.
See the full 10-stage process →
Try it yourself
Take your locked brief and spec. Generate at least three genuinely different forms for the product, not three flavours of one. For each, write one honest line on whether it meets the brief, hits the spec numbers, and can be made at your cost. Cross out anything that fails a wall. Pick the survivor on evidence, not on which sketch you fell for. Start the Free Sprint → if you want a structured first pass.
Your concept checklist
Project notes: four boxes, one survivor
▸ From the notebook · optional reading
Concepting the proofing box with Dan and Anna Hartley in Stockport, and how the prettiest concept lost to the dullest one.
3 min read · click to open
With the brief and spec locked, Dan wanted to start CAD on the lidded crock he had already sketched. I asked for three more forms first. We worked up four on a single sheet: the crock, a domed cloche over a base, a pull-out drawer, and a plain double-wall insulated tub.
The screen we ran
I drew three columns on the whiteboard: brief, spec, cost. Every concept had to earn a tick in all three or it was out.
The crock. Lovely object, cheapest to fire in Stoke-on-Trent. But lifting the lid to check the dough dumped heat, and our 26°C ±0.5°C target died every time the kitchen door opened. Failed the spec.
The cloche. Anna’s favourite, genuinely beautiful. A tall ceramic dome is heavy, awkward to fire without cracking, and it pushed the bill of materials toward £70. Failed cost, and the maker in Stoke-on-Trent was honest that the reject rate worried him.
The drawer. Held heat well, felt premium. But sliding ceramic on runners is a cost and a warranty risk, and against UKCA and BS EN 61010 it added a moving part near the heater I did not love. Marginal.
The double-wall tub. The least exciting sketch on the sheet. An insulated double wall held the temperature on under 30W, took the two 1kg balls, fired cleanly, and landed at £38–55. It ticked all three columns.
What this stage was really for
Six months earlier the team would have tooled the crock because Dan liked it. The screen made the decision boring and right. Anna let the cloche go once she saw it on the cost line next to the others, and the wood cladding we added later gave the plain tub the warmth she wanted anyway. The point of concept brainstorming is to let the cheap medium of a sketch kill the wrong forms before expensive tooling commits you to one.
— Design stage, project notes, 2026
— Next in Design → Sketch ideas