All simple isometric lines such as in this particular example have a simple rule you should always follow for clean results. See Figure 1.2 below, which explains how the simple rule works and how to achieve this with every one of your lines.

Figure 1.2

The rule takes upon the basic concept of every 1 pixel you draw moving in either an up or down direction, you have to move 2 pixels across. So if you were looking at this line from a birds eye view it would appear straight up and down, vertical. But since this is isometric it needs to be skewed slightly. Apparently the angle of an isometric line is near 30°, but then again it could be exactly 26.565°. Below is an example of how not to draw your isometric lines. I mean you can draw them like that if you really, really want to, but in my opinion it always ends up looking messy and really weird to look at. The example below is 30° and as you can see it looks slightly off, that’s why the isometric line is not exactly 30°.

Figure 1.3

I think that is all we really need to cover about lines. It’s all really basic stuff and most people get it the first time they try. If you don’t just keep practicing and looking at examples. Below are a few different variations of the line, showing different ways you can use it. And yes, horizontal and vertical lines are acceptable, and yes you can break the simple rule, but please people, only if the line ends up looking clean and fits well into the picture.

Figure 1.4