Anatomy of a 3D Object

Fig 1: The basic elements of a 3D object

When editing an object in 3D software, there are 3 main elements we can alter; vertexes, edges and polygons.

The vertexes are the most basic elements and can be found on the corners of an object.

The edges are lines that connect the vertexes.

If an area is enclosed by edges and filled in, this forms a polygon (sometime known as a face).

When we edit any of the elements of an object, we will usually affect the surrounding elements as well.

In the following example I have moved one vertex on a cube. By doing this, I have altered the surrounding edges and faces connected to that vertex.

Fig 2: The cube before editing

Fig 3: The cube after editing

Using simple changes to these 3 basic elements, we can change the primitives into something totally unique.

Basic Principles of 3D

2D images are defined as having height and width. In digital images the width of an image is defined by the "x" axis and the height by the "y" axis.

When describing image resolution we always state the width followed by the height. For example a high definition TV screen would be 1920 x 1080px.







In the early days of video games nearly all games were exclusively 2D.

This was mainly due to the limitations of the available hardware.

3D images have height, width and depth. The depth information is defined by the "z" axis.


Early 3D images were quite primitive, with little detail and no shading. As the technology improved, 3D graphics became more advanced.

Today 3D images can be seen in many forms from big budget movies such as Avatar and Toy Story to television adverts for products such as toilet duck. 





 Video games have also progressed to the point where the majority of big budget titles feature 3D graphics.

The next big development in 3D graphics is likely to be the use of glasses to produce stereoscopic 3D images.

Rasters Vs Vectors

Raster images are made of a series of pixels arranged into a grid. Each pixel has colour and brightness information.

Photoshop logo JPEG and zoomed in section showing individual pixels

Raster images can display a wide range of colours and are ideal for photographic images. However when a raster image is enlarged the pixels become bigger and more obvious. This causes edges to become jagged, especially curves.

Vector images are created using sets of co-ordinates joined by lines. This means that the image can be enlarged by moving the points without affecting the quality of the line

Cartoon created in Adobe Illustrator and zoomed in section at 2400%, the line is still sharp

Vector images are very useful for creating line art such as the above cartoon and for logos and icons. However, they are limited when trying to display graduated shades of colour.

 Sunset image as a jpeg compared to a vectorised version created in Illustrator

For more information on vectors and rasters, have a look at this video from vector.tutsplus.com.