The following pictures are not actually real photo's, but are 3D drawings produced using Autocad.
There are various ways of representing an object within a computer, the most common is to draw the object as seen from 3 different view points, this is know as an orthographic projection and shows the object from above (plan view) from one side, and from the adjacent side. This gives a reasonable representation of what the object looks like, but needs a bit of imagination to visualize what it would look like in real life.
This is all very well but the viewpoints are set in stone so to speak, any other viewpoints you wish to see would have to be drawn seperatly which is quite a complex task with some objects.
A better way, but obviously more complicated one is to draw the actual object as a true 3d model within the computer, this means that as well as the x y plane you also have to take into account the z plane (height or depth). One drawn this model can then be moved or rotated in any direction or plane you so desire. With Autocad you can also apply a material to the object (known as rendering) which not only makes it look more real but also gives it a solid feel.
A further enhancement is to place the object in question against a background of some description and add texture or render that as well. The final touch required to add realism is to add a light source of given intensity and direction, from this the computer can calculate (quite slowly sometimes as this is a very complex task) just where and how big the shadow cast by the object will fall.
The description given above is exactly the approach I take when producing a 3d drawing of an object.