IB Design Technology Topic A2.2.5: CAD for Virtual Prototyping Notes

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; 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; 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.

1. 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; digital humans are computer models of human bodies that stand in for real user groups, from children to elderly users to people with disabilities.

1. Placed in a virtual workspace or vehicle, they reveal fit, reach, comfort, and safety problems early.