We'll be creating the pattern used in this visual. It looks a bit like a diamond shape. Below is an image showing the different steps it takes to create this pattern:
Looking at the steps now, you would think it's all clear at the very start and such pattern is created in no time. In a way you are right of course, once you're done analysing, the work is done and things go fast. It's the analysing that I find the most difficult, and also keeping in mind that it has to be easy explainable in a tutorial, in other words by using simple steps with simple tools and just values to rotate, scale etc.
To make a visual distinction between each step, I've decided to use a different stroke color. Feel free to use whatever you like. You might even try using a transparent fill instead (or a combination), and experiment with the Blend Mode options. Of course you can edit anything at all times, so no worries if the result is not to your liking when you start creating this object. As usual, I'm sure there are different ways in how this could be created, but here is my way:
Draw an octagon
Start by drawing a vertical and a horizontal guide on your canvas. Also, make sure you have Smart Guides turned on (View > Smart Guides). Select the Polygon tool, hold down the Alt/Option key and click exactly on the intersection point of both guides. In the window that appears enter a value for the radius (100 is fine), enter 8 sides, and click OK.
Draw a diamond shape
Next select the Pen tool and draw a diamond shape as shown in the image above: click the interestion points of the guides and the polygon shape. Make sure you have Smart Guides turned on so you'll get some visual help (a small square appears) to click in these exact points.
Copy rotate the diamond
Copy the shape (Cmd/Ctrl + C), and Paste it in Front (Cmd/Ctrl + F). Rotate the shape at exactly 45° from the center out. Select the Rotate tool, click exactly in the center point and start rotating/dragging while holding down the Shift key. You can of course also choose to hold down the Alt/Option key while clicking in the center point, enter 45° in the window that appear, and hit the OK button.
Copy rotate the polygon
Now select the polygon shape, and select the Rotate tool. Hold down the Alt/Option key and click again in the center point. In the window that appears enter 22,5°, and hit the Copy button.
Scale the polygon
With the polygon shape, still selected, select the Scale tool, hold down the Shift key, and scale the shape down until it fits exactly into the square. Again, make sure your Smart Guides are turned on as this will help you by showing when it reaches this point.
Draw a star
Now select the Pen tool and draw the connecting lines as shown in the image above. Again, the Smart Guides will help you find these exact points easily by showing a visual clue.
Select the entire object, and select the Scale tool. Hold down the Alt/Option key, and click in the exact center point again. In the window that appears, enter 60%, and hit the Copy button.
Draw 6 lines
Select the Pen tool, and draw these 6 separate lines as shown in the image above.
Turn into a pattern
Select the entire object, and change the value of its dimensions in the Options bar at the top to 200px width and 200px height. This way we're dealing with easy numbers in our next step when we turn this object into a pattern file. Go to Object > Pattern > Make. Click OK in the message that appears. In the Patterns panel, make sure the dimensions of the tile matches the dimension of the object. That's it!
It's always good to create a couple of variations of the original pattern, or in case the result is not 100% to your satisfaction, to tweak the pattern in Pattern mode (just double click the pattern swatch in the Swatches panel). At the top you can choose to Save a Copy if your intention is to create an extra variation. You can click the Done option in case you've modified your pattern and want to save it.
In the image above I'm showing the pattern I've used in the image at the top of my article. I removed the colors of the lines and made them all white. Then I changed the thickness of the strokes, by using different values. Some of them are also turned into dotted strokes, and I have also added extra diagonal lines in each corner of the pattern tile. Then last but not least, I've added some transparent fills in certain areas, by drawing shapes below the lines. Once I applied the pattern I rotated it 45° without rotating the object. Remember you can scale or rotate an object's pattern, without rotating or scaling the object itself. Just select your object, then select the Rotate or Scale tool depending on what you want to do, hold down your Option/Alt key, and click on your canvas. Then in the window that appears, check the option Transform Pattern to rotate or scale the pattern, and make sure to uncheck the Transform Object option. To see what will happen before clicking OK, check Preview.
Keep on experimenting
With this tutorial I also wanted to take things one step further, but it seems I'll need a bit more time. You see, I have the opportunity to experiment with SymmetryWorks by Artlandia, an Illustrator Extension to help creating complex patterns. It seems a very powerful tool as you can do a lot of crazy things with it, things not really possible with Illustrator's pattern feature. So for people who are searching for a tool to help creating complex patterns, you might want to check it out. There are a lot of options you can try out on the fly. In fact you can do so much that you quickly end up with a result you didn't expect (good or messy bad). I will spend a bit more time getting to know it better, and when I do I'll share my experience here on my blog. So stay tuned! In the meantime, I hope I sparked some ideas. Keep on experimenting!