Learning Objectives

✅ I can explain how computers create 3D shapes.
✅ I can describe the difference between 2D and 3D objects.
✅ I can use TinkerCAD to create and modify 3D shapes.

Key Ideas: How Computers Store 3D Shapes

Computers store and display 3D objects using a coordinate system based on three axes: X, Y, and Z. The X-axis controls movement from left to right, the Y-axis controls movement up and down, and the Z-axis controls movement forward and backward, creating the sense of depth that makes an object appear three-dimensional. Unlike 2D shapes, which are flat and have only width and height (such as a square or circle), 3D shapes are solid objects that have width, height, and depth (such as a cube or a sphere). Computers build 3D models by using a collection of polygons, which are flat shapes with straight edges (such as triangles and squares). These polygons are connected to form a mesh, which creates the surface of a 3D object. The more polygons a model has, the smoother and more detailed it will look, whereas models with fewer polygons may appear blocky or rough.

Once a 3D model is created, computers must render it in order to display it as an image. Rendering is the process of calculating how light interacts with a 3D object to create realistic effects, such as shadows, reflections, and textures. This is especially important in video games and animations, where 3D models need to look as realistic as possible while running efficiently on a computer. Since computers cannot store real-life objects, they store 3D models as a collection of numbers and coordinates, tracking the position and shape of each polygon. These models are saved in special file formats, such as STL and OBJ. STL files are mainly used for 3D printing, while OBJ files can store additional details such as colors and textures, making them useful for games, movies, and animations.

Video games rely on polygons instead of real objects because they are much easier for computers to process. A real object contains infinite detail, but a polygon-based model allows designers to create simple and efficient 3D shapes that look realistic while still running smoothly. These models are placed onto a workplane, which acts as a flat surface where 3D objects can be positioned, moved, rotated, and resized. In TinkerCAD, the workplane helps designers organize their models by providing a clear grid to place and align objects. When adjusting objects in TinkerCAD, users can rotate them by clicking and dragging the rotation arrows, which allow them to move objects along the X, Y, or Z axes. By using these tools, designers can create, modify, and refine 3D models efficiently.