Lesson 27 · Unit 4

Physical vs Virtual
Prototypes

Choose between tangible models and digital simulations based on what must be experienced, measured or predicted.

80 minutesA2.2.3–A2.2.5Physical + CAD

Guiding question: What can a physical prototype reveal that a virtual prototype cannot—and vice versa?01

Today’s destination

By the end of class, you should be able to…

Explain prototype purpose

Discuss why designers prototype during product development.

Use physical prototypes

Explain testing of scale, aesthetics, materials, function and performance.

Use virtual prototypes

Explain CAD-based testing including surface/solid models and advanced simulation tools.

Choose strategically

Select physical or virtual methods based on the evidence needed.

Success check: explain the concept accurately, then use it to make a justified design decision.

Know it → use it → explain the evidence.02

A2.2.3

All prototypes exist to reduce uncertainty.

A2.2.3: prototypes can be physical or virtual, but both should gather insight that moves development forward.

Represent

Make the idea inspectable

Turn assumptions into something a user or team can examine.

Test

Generate evidence

Reveal performance, interaction, fit, form or failure.

Refine

Drive the next change

Feedback and data should influence the next iteration.

A prototype with no learning purpose is just a model.03

A2.2.4

Physical prototypes make interaction tangible.

1:2

Scale

Test overall size, reach, fit and spatial relationships.

FORM

Aesthetics + materials

Evaluate surface, texture, visual proportion and material feel.

TEST

Function + performance

Operate mechanisms, apply loads, observe errors and gather user feedback.

Physical prototypes are especially strong when body/product interaction matters.04

A2.2.5

CAD creates testable digital representations before physical manufacture.

Change dimensions or geometry quickly.

Inspect form, assemblies and spatial relationships.

Simulate users, motion, forces or environments.

Prepare geometry for rapid prototyping.

Digital does not mean “less real”—it means a different kind of evidence.05

CAD model types

Surface and solid models represent geometry differently.

Surface model

Focuses on the outer skin / form.

Useful for complex free-form surfaces, styling and controlled curvature.

↔

Solid model

Represents a complete volume.

Useful for mass, sections, assemblies, interference and manufacturing operations.

B2.2.3 later requires students to construct and interpret surface, solid and virtual models.06

A2.2.5 complete vocabulary

Virtual prototypes can simulate more than shape.

Generative design

Algorithm explores alternatives

Generates candidate forms under goals and constraints.

Digital humans

Human-size simulation

Helps assess reach, clearance, posture and interaction.

Motion capture

Record movement

Captures body motion to study real interaction.

Haptic technology

Simulate touch / force

Provides tactile feedback in virtual interactions.

These tools extend CAD from geometry into behaviour and interaction.07

A2.2.5

Three more ways to test before committing to hardware.

Virtual reality

Immerses users in a simulated product/environment for spatial and interaction testing.

Augmented reality

Overlays digital content on the real world to test placement, scale or interaction in context.

FEA

Finite element analysis

Simulates how a part or assembly behaves under defined conditions such as loading.

Interpret the output: if FEA shows a high-stress region, relate it to the loading assumptions, material and model limits; then refine geometry/materials and validate physically where appropriate. A colour plot is evidence, not automatic proof.

A2.2.5 + B2.2.4 · use FEA and interpret its output critically.08

Apply it

Physical or virtual first?

A designer needs to check whether a proposed cabinet door will collide with another component across its full motion path before building a full-size prototype.

Which method is most efficient first?

Choose before you reveal the feedback.09

Combine strengths

Strong development often moves back and forth between digital and physical.

CAD concept

Control geometry and compare dimensions.

Rapid physical model

Check handling, fit and user response.

Update CAD

Respond to test evidence.

Higher-fidelity prototype

Test integrated function/performance.

The best workflow uses the cheapest method that answers the current question.10

Apply it

Match the evidence need to the medium.

Need	Physical	Virtual
Real grip feel	Strong	Limited unless specialized haptics
Fast dimension changes	Slower	Strong
Real material surface	Strong	Approximate
Interference / motion simulation	Possible	Strong
End-user handling	Strong	Possible with VR/AR/haptic systems

Choose evidence quality—not your favourite tool.11

Vocabulary lab

Virtual prototyping vocabulary

Retrieve first. Then check.

TermPhysical prototypeClick to reveal

MeaningA tangible representation used to test aspects such as scale, aesthetics, materials, function and performance.

TermVirtual prototypeClick to reveal

MeaningA digital representation used to explore, test or simulate aspects of a product before/alongside physical prototyping.

TermSurface modelClick to reveal

MeaningA CAD model focused on the outer surface geometry of an object.

TermSolid modelClick to reveal

MeaningA CAD model representing a complete 3D volume.

TermGenerative designClick to reveal

MeaningAlgorithm-supported exploration of candidate solutions based on goals and constraints.

TermDigital humanClick to reveal

MeaningA virtual human representation used to evaluate interaction, reach, clearance or posture.

TermMotion captureClick to reveal

MeaningTechnology that records movement for analysis or virtual simulation.

TermHaptic technologyClick to reveal

MeaningTechnology that provides or simulates tactile/force feedback.

TermVirtual reality (VR)Click to reveal

MeaningAn immersive simulated environment.

TermAugmented reality (AR)Click to reveal

MeaningDigital content overlaid onto the physical environment.

TermFinite element analysis (FEA)Click to reveal

MeaningSimulation that predicts how a part/assembly may perform under specified conditions.

Say the meaning before you flip the card.12

Knowledge check

Can you retrieve it without looking back?

1. Name the five physical-prototype aspects listed in A2.2.4.

Scale, aesthetics, materials, function and performance.

2. Name the virtual prototyping techniques listed in A2.2.5.

Surface and solid models, generative design, digital humans, motion capture, haptic technology, VR/AR and FEA.

3. When is a physical prototype usually stronger than CAD?

When realistic touch, material feel, handling or embodied user interaction is the evidence needed.

4. When is CAD usually stronger?

When fast geometry changes, digital analysis, interference checks, simulation or preparation for rapid prototyping are needed.

Say the answer first. Then reveal it.13

Exit ticket

Before you leave…

1. Choose one IA design question best answered physically.

2. Choose one best answered virtually.

3. Name one advanced virtual-prototyping technique and what it can test.

Next lesson

Rapid Prototyping & CAD Overview

Keep the evidence chain moving: user → research → decision → test.

Curriculum alignment
A2.2.3 purpose of physical/virtual prototypes · A2.2.4 physical prototype testing · A2.2.5 CAD/virtual prototyping techniques.

Lesson complete14 slides

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IB Design Technology SL · Lesson 2714

Physical vs VirtualPrototypes