Lines / Templates
The very very basic thing you need to know in order to set up a decent domino track is how to build a simple line. This is how:
It's not only about lining up dominoes "somehow" so that it looks like they will topple - no, you do need to pay attention to the space between them. The perfect distance is exactly once the thickness of a domino. So if you set up a bunch of dominoes pressed together and then removed every second domino, the result would be a perfect line. But there's an easier way to get to that result - a tool called template or fork.
A domino template basically looks like a comb; the dominoes fit exactly into the gaps between its sprockets, thereby helping you set up a perfect line. Here's a picture:
If you manufacture a template (you usually don't, see "Notes") make sure that its gaps are in fact a bit wider than a domino is thick. Otherwise the dominoes will get stuck in the gaps.
When using a template, you first place the dominoes in the gaps, either one after another or several of them in a row (there are certain techniques for that, you will most likely find one for yourself that you get used to), and then carefully pull back the template. The result is a perfectly straight line with the ideal distance between the dominoes.
1. Most templates have 20 gaps.
2. Various materials are suitable for making a template, but the most simple way to make on is LEGO. Thanks to a lucky coincidence, the smallest LEGO bricks turn out to have exactly the perfect size to be used in a template.
There's not a lot to be explained about turns. A turn of 90 degrees should include at least 6 dominoes. (It needs more if you use "Domino Express" since the "hollow" shape and the lower weight of these dominoes make turns with them more chancy, so you should at least use 10 dominoes.) At CDT, it's a rule to use 10 dominoes in every turn. Like that, using more dominoes that are basically necessary, we make 100% sure that no turn sheers out of course.
A double line is just what the name indicates. Instead of just having one row, you build a second one parallelly next to it. That improves the design of a project because the lines looks less slim and "lonely".
There are basically just two things to pay attention to:
1. For the best visual result, the space you leave between the two lines should be as much as the thickness of one domino (so exactly the same as between the dominoes).
2. Always after a few metres of a straight line, and before and after each turn, you should add a third domino at one point in the line, just as shown on the photo. The purpose of that is to make sure the lines keep falling "in lockstep".
The same things are true for double-lined turns. Just build two turns next to each other and remember to add the blocks of three dominoes before and after them.