As the saying goes "A picture is worth a 1000 words". This picture helps you visualize (imagine) what this box would look like if you were holding it in your hand. This is much easier than reading a description of the box: "The box is a rectangle and is 3 inches in height, 6 inches wide, and 9 inches long. Each face of the box has a different color on it: red, green, yellow, blue, purple, orange." But wait a minute, you can't see all the colors! This is because the box is really a 3-dimensional object. In the picture you can not see all sides of the box. The picture of the box just like a photograph is a 2 dimensional (flat) representation of a 3-dimensional object.

Engineers and other individuals who build or manufacture products have adopted ways of communicating this type of information. They use drawings and other graphics methods to represent 3-dimensional (objects with height, length and width).

You may have heard terms like "drafting", "CAD" or "computer aided design", "blueprints", "patterns" or "views". What do they mean?

To explain this, let's go back to our example of the multi-colored box. This time let's label each of the box's sides and introduce some new terms. This picture of the box is called an "orthographic projection" which is a projection of faces at right angles to form a "3D" view. Engineers frequently say that it is an "orthogonal view" for short. What if we looked at the box so that you only see the front, back, top, bottom, right or left side. These are called "views". Although you can only see one side at a time, you now know what each part of the box looks like. No part is hidden.

Here are two more diagrams of a cube. Note the dotted lines. These are called "hidden lines". Hidden lines show you the shape of an object almost as if you could see through the object.

Now you know what the box looks like, but we do not know how big the box is from these views - we do not know the "dimensions" (the box's measurements). Without the exact measurements (how many inches or centimeters each part is) you are not able to build the box. If the drawings are to "scale" then you know how big one part is in relationship to another. A scale is a proportion or ratio. For example on a map you may see a scale like "1 inch = 10 miles" - each inch on the map represents 10 miles.

Blueprints are photographic reproductions of architectural or engineering plans. Typically the lines are drawn in white on a blue background.

Engineers and other professionals use drafting diagrams to communicate the shape and dimensions (measurements) of an object. In the past, all drafting was done by hand. Today, the same drafting diagrams are often created by engineers using Computer Aided Design or CAD software packages. Many of the computer software packages are smart enough to generate some of the views. The object can be rotated on the computer's monitor. Some packages even calculate the amount of materials needed to make the object and help determine how the parts should be manufactured.

If you have ever sewn clothing or even made a kite you know that you lay out the pattern on the material and then cut around the pattern. To make a dress the separate components of the dress pattern are sewn together based on the instructions. The final shape of the dress does not look very much like the original flat patterns.

To build a kite, you form the body of the kite and then add lines, a bridle and perhaps even a tail. These "flat patterns" become the object. The flat patterns are not the same as the drafting diagrams. The drafting views show you how an object looks from all sides. The flat pattern forms the actual object.