A2.2C CAD for virtual prototyping

Virtual Prototyping: Test the Design Before You Build It

1. Virtual prototypes were introduced in A2.2.3; because a CAD model costs almost nothing to change, a team can run many iterations quickly, trying and discarding ideas that a physical prototype would make slow and expensive.
2. Beyond the cost, speed, and sharing benefits already seen, a virtual model can be tested, not just viewed: assign it real material properties and you can simulate the stresses, loads, and impacts it will face, animate components to spot clashes, and find weak points before the first physical part is cut.

Modelling Methods: Surface, Solid, and Generative

1. Surface modelling defines only the outer skin of a product, its form, curves, and aesthetic appearance, with no thickness or interior.
2. It builds complex shapes fast, so car and consumer-product designers use it to refine looks, but you cannot section it or manufacture from it.

1. Solid modelling defines the whole object, including volume, mass, and internal structure.
2. The software can calculate properties like centre of gravity, and a change to one part ripples through automatically, making solid models the basis for functional testing, CAD/CAM, and FEA.

Generative design goes further: you give the software goals like a target strength, material, or weight, and its algorithms generate optimised variations, often organic, lattice-like structures that hit the target using the least material.

Simulating the User: Digital Humans, Motion Capture, and Haptics

1. Some CAD tools test a product on a virtual person before a real one touches it.
2. Digital humans are computer models of human bodies that stand in for real user groups, from children to elderly users to people with disabilities.
3. Placed in a virtual workspace or vehicle, they reveal fit, reach, comfort, and safety problems early.

Motion capture records how a real person actually moves, using sensors or cameras, and maps that movement onto a digital model, so teams spot awkward movements and ergonomic flaws in sports gear, wearables, and games.

Haptic technology closes the loop by simulating touch: it applies vibrations, forces, or resistance so a user can feel a virtual product, which is why it appears in medical training and VR prototyping.

Together these tools test how a person fits, moves, and feels against a design long before it exists as a physical object.

Immersive Review: VR and AR

Virtual reality puts a designer or user inside the model: through a headset, a fully immersive digital environment replaces the real world, so you can walk through a building or sit in a vehicle that does not yet exist, which makes VR ideal for judging scale and space and gathering early feedback.

Augmented reality works the other way: instead of replacing the world, it overlays digital models onto it through a phone, tablet, or glasses, so a shopper can see how a sofa looks in their own room, which is why AR shows up in retail, marketing, and product configuration.

The difference is simple: VR replaces the environment, while AR adds to it.

Finite Element Analysis: Simulating Physical Stress

1. Finite element analysis (FEA) simulates how a design responds to physical forces: the software breaks the model into a mesh of small elements joined at nodes, then calculates how loads spread through it, testing stress, deformation, thermal effects, fatigue, and vibration.
2. The result is usually a colour map, cool colours where stress is low and hot colours where it concentrates, showing the weak points to strengthen and the overengineered areas where material can be trimmed to save weight and cost.
3. FEA does not replace physical testing: the simulation flags likely problems, and a physical prototype confirms the final design meets its specification.