Discover how physical 3D shapes are represented digitally — and take your first steps in CAD thinking.
Learn — read and understand
From physical to digital — the same shapes, a new medium
Every 3D shape you have built physically — cubes, cylinders, spheres, pyramids — exists as a digital object in CAD (Computer-Aided Design) software. The software does not invent new shapes. It gives you precise digital tools to create, resize, combine, and modify the shapes you already know.
Primitives: the building blocks of all digital models
In CAD software, the basic shapes are called primitives: cube (box), sphere, cylinder, cone, torus (donut shape), and pyramid. Every complex object — a car, a phone, a building — is built by combining, subtracting, or modifying primitives. Learning to think in primitives is the first step toward digital modeling mastery.
Boolean operations: add, subtract, combine
The three fundamental CAD operations are Boolean operations: UNION (combining two shapes into one), SUBTRACTION (removing one shape from another — how holes are made), and INTERSECTION (keeping only the overlapping part). Understanding Boolean operations unlocks infinite design possibilities.
Coordinates: where objects live in digital space
In digital 3D space, every point has three coordinates: X (left-right), Y (forward-backward), and Z (up-down). When you move an object in CAD, you are changing its coordinates. This coordinate system is the same one used by engineers, architects, and game designers worldwide.
Explore — tap to see digital modeling concepts
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Box primitive
The digital cube. Resize along X, Y, Z to make any rectangular shape. The most commonly used primitive.
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Boolean Union
Two shapes become one solid object — like gluing them permanently. Example: cylinder handle + cube body = mug.
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Boolean Subtraction
Shape B removes its volume from shape A — this makes holes. Like a cookie cutter cutting through dough.
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Scale and resize
Every dimension (X, Y, Z) can be changed independently. A box at 100×100×5mm = tile. At 10×10×50mm = pillar.
Activity — match each CAD operation to what it produces
Drag or tap a label, then drop/tap on a zone
Union
Subtraction
Scale X only
Move Z axis
Creates one merged solid
Creates a hole
Makes object wider only
Moves object upward
Quiz — CAD and digital shapes, 5 questions
1In CAD software, basic shapes like boxes and spheres are called…
2How is a HOLE created in a digital box in CAD?
3In the 3D coordinate system, the Z axis controls…