---
title: "CAD and Making by Machine"
description: "A design drawn on a computer can be sent straight to a machine that cuts, prints or mills it. What the machine can and cannot do reaches back into the design, which is why the drawing changes once you"
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source: https://lightmysky.com/learn/design-and-technology/cad-and-making-by-machine-mt_jNf8g85YbY.md
retrieved: 2026-09-12
---

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# CAD and Making by Machine

A design drawn on a computer can be sent straight to a machine that cuts, prints or mills it. What the machine can and cannot do reaches back into the design, which is why the drawing changes once you know how it will be made.

Subject: Design & Technology · Area: Designing & Making · Ages 14 to 16
Page: https://lightmysky.com/learn/design-and-technology/cad-and-making-by-machine-mt_jNf8g85YbY

## Ready when they can

- Say what a CAD model holds that a paper drawing does not
- Name three machines that take a digital file and what each is good at, such as 3D printing, laser cutting or CNC milling
- Give one constraint a 3D printer imposes on a shape, such as overhangs needing support
- Explain why a part is redesigned once the making method is chosen

## Lesson: Draw it so a machine can make it

A CAD model holds exact sizes, shapes and depths a machine can read straight in. A paper sketch shows the idea, while the model carries the numbers the cutter needs.

**Example.** One file can feed three machines. A 3D printer builds small complex shapes layer by layer, a laser cutter slices flat sheet fast, a mill carves hard blocks with precision. Each is good at different work.

What the machine cannot do reaches back into the drawing. A 3D printer cannot float plastic in air, so overhangs need support or a new shape, and the design changes.

**Tip.** Pick the making method before you finish drawing. A part for printing looks different from the same part cut from sheet, so redesigning late wastes hours.

**Recap.** Model exact numbers, match the machine to the job, and let its limits shape the drawing.

## Practice

8 questions on this page, each with its working shown.

## Needs first

- [Drawing a Design So Someone Else Can Build It](https://lightmysky.com/learn/design-and-technology/drawing-a-design-so-someone-else-can-build-it-mt_8ezErqUhZw)
- [Iterative Design and Prototyping](https://lightmysky.com/learn/design-and-technology/iterative-design-and-prototyping-mt_fYD3KaViOZ)

## Opens up

- [Making One, Making Thousands](https://lightmysky.com/learn/design-and-technology/making-one-making-thousands-mt_0wbzsY10cQ)