This article will teach you how to use Illustrator’s Create Object Mosaic command to transform your digital designs into a geometric grid-based pattern, for output using any analog media. Anything that can be constructed using tiles or a grid-based structure, can be charted and planned out in Illustrator using this technique. I am a knitter, so I used this technique to create a charted-color knitting pattern (a knitting technique known as intarsia). Here is a simple color charted pattern I made using tables. While InDesign tables are a handy tool for creating charted-color patterns, as the table gets larger, it can grow unwieldy.
For years, I have been on the hunt for a simple solution to convert images into a grid-based pattern that I could knit. The challenge was finding a solution that met a few requirements:
- I needed a non-square rectangle for each stitch (knitting stitches have a ratio of approximately 4W x 3H). In other words, they are squatty little rectangles.
- My knitted designs only have a few colors, so I needed to be able to easily edit all the individual rectangles to reduce the number of colors to match the yarn colors I’m working with.
- I needed to be able to add vertical and horizontal lines to the design, delineating each row and column.
- I wanted the process to be somewhat automated, because I didn’t want to have to colorize each cell by hand. I want the computer the do most of the work for me.
The solution? Illustrator’s Object Mosaic. Now, let me me say that I had been using Illustrator for over a decade before I even knew that this feature existed. I discovered this feature in a book about using Illustrator for fashion design.
1. Start by choosing a simple piece of artwork that you want to turn into a grid pattern. Choose something that has just a few colors. I chose the logo for my beloved Raleigh InDesign User Group.
2. Simplify the colors. I removed all the gradients and converted it into a plain 3-color design.
3. Calculate the required proportion for rectangles. You’ll need to do a little math here. Knitting patterns generally use a term called “gauge,” which is usually done in a 4″ x 4″ swatch. My 4″ gauge switch was 20 stitches W and about 25 stitches H (which equates to 5 sts/inch wide x 6.25 rows/inch high).
4. Calculate how many rectangles you’ll need. I wanted my finished piece to be about 36″ wide x 36″ high.
Width: 5 sts/inch x 36 in = 180 sts
Height: 6.25 rows/inch x 36 in = 225 rows
5. Select your artwork and try to apply Create Object Mosaic. I say “try” because as you’ll notice in the screenshot below, the Object Mosaic command may be grayed out.
Maybe you figure, as I did, if you start with a vector object and you’ll be ending with a vector object, then you can work with vector objects all throughout the process. Not so! Apparently, Object Mosaic only works on raster objects.
6. Rasterize your artwork. Choose Object > Rasterize. My artwork was about 5.9 inches square and I rasterized it at 300 PPI.
7. Select your artwork and apply Create Object Mosaic. Choose Object > Create Object Mosaic. This is where you’ll plug in the numbers you calculated in Step 4.