Time for action – displaying aliasing

The best way to understand aliasing is to see it using the following steps:

1. Create a new file in Blender.
2. Press F12.
3. Press Ctrl + MMB and use the mouse to zoom into the rendered image so that you can see only the corner of the cube closest to you. It should look like the following image on the left.
4. In the Anti-Aliasing subpanel of the Properties window, uncheck the Anti-Aliasing checkbox.
5. Press F12.
6. Now, what you see looks like the right half of the following image, with a jagged line where different surfaces meet.
   

What just happened?

When you unchecked the Anti-Aliasing checkbox and rendered the cube, the three sides of the cube you could see were different shades, and the edge between them was jagged with no shading, as shown on the right. These jagged lines are called Jaggies and should be avoided. When you turned back on the Anti-Aliasing, the edges are less jagged, with lots of interim shades at the edges, as shown on the left. This looks cleaner...