This is my personal thoughts, opinions and musings place. I will also rant about things, especially politically-correct things that irritate me. And sci-fi. Did I mention sci-fi? There'll be lots of sci-fi stuff here. And movies, too. Mmmmm... Movies

Monday, July 18, 2005

Reality and the world of 3D - Part 15

- Continued 5

In the previous section, you learnt about resolutions and the differences between paper canvas and computer screens. Let's now look at what this means for painting on a computer.

Because a computer painting canvas is constructed of a limited number of dots, you are forced to paint differently. Each dot can only have one color; you cannot paint half a dot green and the other half red, for example. This means if you need a color dot somewhere, it must be a whole dot, even if it sticks out from other dots; this makes for jagged lines. Take a look at the circle you drew in Paint in the previous section. Do you notice how jagged the circle is? Do you also notice how smooth the side lines and the top and bottom lines are? This tells you that lines running at right angles to the axis will appear smooth, while lines running at other angles will not; lines running at 45° angles will be smoother than lines running at other angles. This problem is ubiquitous in the digital image world; even digital photography suffers from it.

In fact, this problem is so wide-spread that it even has it's own name. The problem of jaggies(jagged portions) that result from lines running not at right angles to the axis is called “”. And since it has a name, you might be tempted to think that there is a solution to the problem of “aliasing”. Guess what! You would be right. The solution also has a name, a brilliant, geeky and self-referential name: “”. It consists of filling in the empty spots created by the jaggies with similiarly-colored, though lighter, pixels to create the illusion of smooth lines.

Anti-aliasing is an extremely complex computer algorithm that takes quite a bit of computing resources to perform. Know, however, that whenever you see high-quality computer-generated images, they have all been anti-aliased. I don't, however, know about computer animation. It's possible that computer animation isn't anti-aliased because there may be no need; you wouldn't be able to see the aliasing anyway because the action moves so quickly.

Another way you may be able to overcoming the aliasing problem is to render extremely high-resolution images and then zoom out when displaying them on a computer screen. The problem with this method is that it doesn't actually eliminate the aliasing problem, it merely masks it.

Now that you know about aliasing and anti-aliasing, we'll look at what makes up a three-dimensional scene. Please stay tuned...


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