· Physical Model Prototype

ACTIVITY 08.10.01 · 5 MIN READ

Physical model prototype, felt.

Also called: Rough model · Form study · Block model · Looks-like mock-up

A rough, early physical block you can hold, made to feel size, proportion and ergonomics long before anything works or looks final.

— TL;DR

Make something you can pick up in an afternoon. Foam, cardboard, a 3D print, found objects. It won’t work and it won’t be pretty. It only has to teach you whether the size, weight and proportions feel right in a real hand, on a real worktop.

• • •

What a physical model prototype is

A physical model prototype is the first thing you make that you can actually hold. Not a drawing, not a render, not a CAD file you spin on a screen. A real object, roughly the right size and shape, that lives on the desk and gets picked up. It doesn’t switch on. It doesn’t do its job. It exists so your hands and eyes can tell you things a screen never will.

Build it fast and build it cheap. Foam, foam-board, cardboard, a quick 3D print, a few found objects taped together. The cruder the better, honestly, because a crude block invites you to cut it about and try again. A polished model whispers that the decisions are already made. They aren’t. You are still asking the most basic questions: is this the right size? Does it feel heavy or cheap? Where does the hand naturally go?

In my experience the rough model earns its keep precisely because it is throwaway. Nobody mourns a foam block. So you make three, you saw a corner off one, you pad another out, and somewhere in that mess the right proportion announces itself. A month of careful CAD can’t do that, because CAD has no weight and no edge you can run a thumb along.

First model · the proofing box

What we made it from	A block of high-density foam and cardboard, the full size of the box, with a loose lid cut from the same foam. An afternoon’s work.
What it tested	Whether it sits sensibly on a kitchen worktop, whether the lid lifts one-handed with a dough ball in the other hand, and whether the proportions read premium rather than bulky.
What we learned	The first block was too tall and felt like an appliance. Dropping the height by 30mm and widening the base made it sit like a nice piece of kitchenware, holding its two 1kg dough balls without looking like a small fridge.
Cost & time	Under £15 of foam and board, one afternoon. Set against a finished BOM of £38–55 and a £149 retail price, the cheapest learning in the whole project.
What it isn’t yet	It doesn’t heat, hold temperature, or carry any electronics. No ceramic, no controls, no testing against BS EN 61010. That all comes later. This block only answers “does the shape feel right?”.

So before any of the hard engineering, a fifteen-pound block of foam reshaped the whole product. That is the trade the rough model offers, and it is a generous one.

✕ The trap

Polishing CAD for weeks, fillets and finishes and exploded views, deciding the proportions on a screen where nothing has weight, then discovering on the first real print that it feels like a small fridge.

✓ The better move

A rough block in a day. Hold it, set it on the worktop, lift the lid with one hand. Let your hands fail it cheaply now, so the CAD that follows is drawn around a shape you already trust.

How it fits the bigger picture

Physical model prototype is activity 08.10.01, the first activity of Stage 08 Develop. It picks up the form decided in Design and turns it into something your hands can judge. What it learns feeds straight into the next activity, the proof of concept prototype (08.10.02), which is where the thing first has to actually work rather than just sit right.

What it can do

It tells you, fast and cheap, whether the size, weight and proportions are right, and whether the basic ergonomics make sense in a real hand. It catches the expensive mistakes, the ones baked into the shape itself, while they still cost a few pounds of foam to fix.

What it can’t do

It can’t tell you whether the product works. It has no heater, no electronics, no function at all. It also can’t settle the final finish or material; a foam block can suggest a ceramic feel but it can’t prove one. That is what the proof of concept and the engineering stages after it are for.

See the full 10-stage process →

Try it yourself

Pick the roughest material you have to hand, foam, cardboard, a fast 3D print, a stack of found objects, and build your product full size today. Don’t make it work and don’t make it pretty. Put it where it will actually live, pick it up the way a user would, and write down everything that feels wrong. Then change it and pick it up again.

Working out whether your idea is even worth a model yet? Start the Free Sprint → and the GPT will help you frame it first.

Your first-model checklist

Built it full size, from the cheapest material to hand, in a day or less Held it and set it where it will really be used, not on a tidy desk Tested the key one-handed actions, the way a real user would do them Wrote down what felt wrong, then changed the model and held it again Resisted polishing it; left function and finish for the stages that come next

Project notes: a worktop, a lid, and a dough ball

▸ From the notebook · optional reading

A foam block on the Hartleys’ kitchen worktop in Stockport, and the 30mm that turned an appliance back into kitchenware.

3 min read · click to open

Dan was itching to open CAD on the ceramic shell. We pushed back: “Foam first. Make it the real size, put it on Anna’s worktop, and let’s see how it feels before we draw a single line.” An afternoon, a sheet of high-density foam, some cardboard and a craft knife.

What the block told us

The first version, sized straight off the early sketch, was too tall. Stood next to the kettle on the worktop it read like a small white appliance, not the premium counter object the gifting buyers wanted. Anna’s words, roughly, were “it looks like something I’d hide in a cupboard.” That single sentence was worth the whole afternoon.

So we cut it down. I asked Dan to take 30mm off the height and widen the base, and we re-cut the foam there and then. The second block sat low and solid, more like a nice ceramic dish than a gadget. It held the two 1kg dough balls comfortably, with room to lift them out, and it stopped dominating the worktop.

The lid was the other lesson

We cut a loose foam lid and had Anna lift it one-handed while holding a (real) ball of dough in the other. The first lid was too fiddly to grip; we added a wider lip and tried again. Within an hour the one-handed lift felt natural, which mattered because a baker’s other hand is always full.

None of this needed electronics, ceramic, or a thought about BS EN 61010. It needed foam, an afternoon, and a willingness to be wrong cheaply. By the time the CAD started, the proportions were already settled and trusted, which is exactly the point of making the rough thing first.

— Develop stage, project notes, 2026

— Next in Develop → Proof of concept prototype