What a Cutaway Model Is and Why It Persuades

A cutaway model is a physical version of your product with a section removed, or with part of the housing replaced by clear material, so a viewer can see the internal architecture: the pump, the filter stack, the battery, the airflow path, the layers of a composite panel. It usually does not function. Its entire job is explanation.

It works because the internals of most products are the reason they cost what they cost, and customers cannot see them. A distributor comparing your $340 water treatment unit to a $190 competitor is looking at two similar boxes. Cut one open on the table and show three stages of media, a stainless manifold, and a serviceable cartridge, and the conversation changes from price to value in about four seconds. No slide deck does that.

When to Build One

  • Trade shows. A sectioned unit next to the finished unit is one of the highest-traffic booth elements there is, because it gives people a reason to stop and a reason to ask a question. Plan it into the booth build described in trade show prototypes.
  • Technical sales where the differentiator is internal. Filtration, sealing, thermal design, materials, redundancy. Anything the buyer cannot see and will not take on faith.
  • Distributor and dealer training. A sectioned unit teaches a channel partner your product in one session.
  • Service and installer training. Trainees learn assembly order and access paths from a cutaway far faster than from a manual.
  • Investor and board meetings. A cutaway signals that the internals are real and designed, not aspirational. It pairs well with the narrative discipline in demoing a prototype to investors.
  • Permanent display. Showrooms, museums, and lobbies, where the model needs to survive years of being touched.

How They Are Actually Built

Sectioning a real unit. The fastest route when production parts exist: cut on a bandsaw or waterjet, then deburr, fill, and polish the faces. Realistic by definition. The difficulty is finishing, because raw cut faces look like damage rather than a display. Edges need cleaning, cavities need filling with tinted epoxy, and cut surfaces need sanding through progressive grits so they read as intentional.

Purpose-built model. Internal components printed or machined as simplified representations, assembled into a housing designed with the cut already in it. More control and a cleaner result, and it can be built before production parts exist, but less credible to a technical audience that knows the real internals.

Hybrid, which is what most good cutaways are. Real components where authenticity matters, made parts where it does not, and clear windows replacing housing panels instead of a full section cut. The window approach keeps the exterior silhouette intact, which matters when the exterior is also part of the pitch.

Clear elements are usually machined or laser-cut acrylic, thermoformed PETG, cast urethane, or an SLA resin part polished or clear-coated to transparency. Each has different optics and different toughness, and the choice is not obvious. Start from acrylic vs polycarbonate, and note that on a display model that gets handled, scratch resistance usually beats impact strength.

Where a clear part is complex or curved, casting is often the answer rather than machining, and the process economics are the same ones described in urethane casting.

Design Decisions That Make or Break It

Where to cut. The plane should pass through the components that carry your message and should avoid slicing something into an unrecognizable smear. A cut at 30 degrees off the obvious symmetry plane often reveals more than a straight half-section. Study it in CAD first with section views, from the actual viewing height and angle people will stand at.

Color coding. The single biggest readability upgrade. Paint the cut faces one contrasting color, or color code by function: blue for cold fluid, red for hot, yellow for the electrical path. Untrained viewers understand a color-coded cutaway several times faster than a monochrome one, and the choices should follow the same logic as any CMF decision on the product itself.

Lighting. Internal LEDs behind clear elements turn a good model into a memorable one. Keep the wiring hidden and the power entry at the base.

Motion. One hand-cranked or motorized moving element inside a static model is worth more attention than a fully static display. It does not have to do the real job at the real speed.

Labels. Small numbered flags with a key card, or etched text on the base. Resist labeling everything; three to five call-outs is the limit for something people look at while standing.

Durability. Assume every viewer will touch it. Bond components permanently, cap sharp cut edges, and mount it to a weighted base. A model that gets shipped to shows needs a foam-lined case designed at the same time as the model.

Cutaway, Appearance Model, or Working Prototype

These three answer different questions and teams routinely buy the wrong one. An appearance model answers "what will it look like" and is what you photograph. A working prototype answers "does it do the job." A cutaway answers "why is it built this way and why is it worth the price." The distinction between the first two is spelled out in looks-like vs works-like prototypes, and the cutaway is a third category neither covers.

So if your differentiation is aesthetic, build the appearance model; if it is functional performance, the working prototype; if it is internal engineering the buyer cannot verify, the cutaway. The finishing work that makes any of them presentable is described in painting and finishing prototypes.

Cost and Lead Time

A simple sectioned unit made from existing production parts, cleaned up and mounted, typically runs $1,500 to $5,000 and takes one to three weeks. Most of that is hand finishing labor, not material.

A purpose-built hybrid with custom clear windows, color coding, and a base runs roughly $6,000 to $20,000 over three to six weeks, driven by part count and how much of the interior has to be fabricated rather than borrowed.

A show-grade model with internal lighting, a moving element, an engraved base, and a travel case runs $20,000 to $60,000 and needs six to ten weeks. Treat that as a marketing asset with a multi-year life rather than a one-off expense. Two scheduling notes: start earlier than feels necessary, because hand finishing does not compress, and build from a design revision you are confident in, since a model showing last revision's internals undermines the conversation it was built for.

Two last practical notes. Photograph the model professionally as soon as it is finished, because those images end up in every deck and proposal and cost far less than the model did. And keep a short written script tied to the call-outs so any salesperson can present it consistently.

Build a Cutaway That Sells the Engineering

Projects House designs and builds cutaway and sectioned display models, from choosing the cut plane in CAD to fabrication, color coding, lighting, and a travel case. Send your CAD or a description of the internals through our contact form and we will propose an approach and a budget.