How to Draw a Simple 4-Division
If you're new to Kimekomi ornament making, learning how to accurately mark your foam ball is one of the first skills you'll need.
Kimekomi is a traditional Japanese technique in which grooves are cut into a molded shape and fabric is tucked into those grooves to create a decorative design. Before you can cut those grooves, however, you need to know where to put them!
In this first video in my new series, I'm focusing on one of the most basic and useful skills: how to divide a foam ball into four equal sections.
A simple 4-division is the easiest place to start, and the skills you learn here will form the foundation for more complicated divisions and designs later.
There are two ways to mark a simple 4-division:
The math method
The paper strip method
Both methods will give you four equally spaced sections. The paper strip method is especially useful if you don't enjoy doing math—or if your foam ball isn't perfectly round.
What You'll Need
For the math method, you'll need:
A polystyrene smooth foam ball
A plastic-type flexible tape measure
A fine-tipped marker, like a Sharpie
A calculator
Note paper
For the paper strip method, you'll need:
Straight pins
A strip of paper, preferably cut as straight as possible with a paper cutter.
Scissors
A fine-tipped marker, like a Sharpie
Method 1: The Math Method
The first method uses the diameter of your ball to calculate its circumference.
1. Find the North and South Poles
Before you begin, mark the North Pole and South Pole of your ball.
Many foam balls used for Kimekomi already have factory markings, such as mold lines and pole markings. If your ball doesn't have these markings, you'll need to find them before beginning. I've made a video showing how to find these basic reference points. You can find that video here.
2. Calculate the Circumference
My ball has a diameter of 8 cm.
To calculate the circumference, multiply the diameter by pi:
8 × 3.14 = 25.12 cm
So the circumference of my ball is 25.12 cm.
Next, divide the circumference by 4:
25.12 ÷ 4 = 6.28 cm
This tells me that each of my four sections needs to measure 6.28 cm along the equator.
For practical measuring, I'll round this to 6 cm and 3 mm.
The same calculation works whether you're measuring in centimeters or inches. If you're working in inches, however, you'll need to convert the decimal portion into a fraction that you can locate on your tape measure. I like to use the following online conversion tools.
https://maniacs.info/ruler/inches-on-a-ruler.html
https://www.inchcalculator.com/inch-fraction-calculator/
3. Mark the Equator
Start by choosing a point on the equator mold line of your ball and make your first mark.
Then, using your tape measure, measure 6 cm and 3 mm along the equator and make another mark.
Continue around the ball until you have four points.
When you reach the final section, it's a good idea to double-check your measurement. If you're off by 1 mm, it generally won't make much difference. If the final section is significantly different from the others, however, it's worth going back and checking your measurements.
4. Draw the Vertical Lines
Now we'll use the tape measure as a straight edge rather than as a measuring tool.
Place the tape measure from the North Pole, through one of your equator marks, and down to the South Pole.
Draw a straight line.
I like to continue the line all the way around the circumference of the ball. This helps keep the line straight and makes it easier to see whether everything is symmetrical.
Repeat this process for the remaining equator marks.
When you're finished, you should have a simple 4-division.
Don't Worry About Being Perfect
One thing I want to emphasize, especially if you're a beginner, is that your lines don't have to be absolutely perfect.
It's easy to become frustrated trying to get every line perfectly symmetrical. But for a simple design, a difference of 1 mm or so generally isn't going to be noticeable in the finished ornament.
Flexible plastic tape measures can also stretch and become slightly distorted with use. If your tape measure has been around for a while, it may not be as straight as it once was.
So if your line is just slightly imperfect, don't panic!
Aim for accuracy, but don't let the pursuit of absolute perfection stop you from enjoying the process.
Method 2: The Paper Strip Method
If you don't want to do the math, or if your foam ball is slightly misshapen, the paper strip method is a great alternative.
This method allows you to divide the circumference of your ball into four equal sections without calculating its circumference.
1. Make a Paper Strip
Cut a long, narrow strip of ordinary copy paper.
The important thing is that one edge of the strip is perfectly straight. I use a paper cutter to cut my strips because it gives me a very straight edge.
This straight edge will be the measuring edge of your strip.
2. Measure the Equator
Draw a mark on the equator of your ball.
Put the straight edge of your paper strip directly on that mark and wrap the strip around the equator.
Continue until the strip meets your starting point again.
Mark the point where it meets the starting mark and cut it to length.
You now have a paper strip that is exactly the circumference of your ball.
3. Fold the Strip Into Four Equal Sections
Next, you'll divide the paper strip into four equal sections.
First, fold the strip exactly in half.
Then fold each end toward the center crease to create two additional creases.
You should now have three equally spaced creases, dividing the strip into four equal sections.
Accuracy is important here. Take your time when folding the paper and make sure the edges line up as precisely as possible.
If you're off by several millimeters when making your folds, those errors will be transferred to your ball.
4. Pin the Strip to the Ball
Place the straight edge of the paper strip along the equator mold line of your ball.
Align it as carefully as possible with the mold line.
Use straight pins to hold the strip in place at each of the creases.
Then mark the ball at each crease.
Once you've marked all four points, remove the paper strip and pins.
Your equator is now divided into four equal sections.
5. Draw the Vertical Lines
Just as with the math method, use your flexible tape measure as a straight edge.
Place it from the North Pole, through one of your newly marked equator points, and down to the South Pole.
Draw your line.
Again, I like to continue the line all the way around the ball rather than stopping at the South Pole. This gives me a chance to check that the line is straight and symmetrical.
Repeat with the remaining equator points.
And that's it!
You now have a simple 4-division.
Which Method Should You Use?
Both methods work well, so choose whichever feels more comfortable for you.
The math method is useful when your ball is very well made, and the packaging accurately indicates the diameter of the ball. Once you're comfortable with the calculation, it's quick and straightforward. If you are using the same size ball for another ornament, the measurements will be the same. Keep a record of your measurements so you don’t need to recalculate.
The paper strip method is particularly useful when:
You don't want to do calculations.
Your ball is slightly irregular, or you don’t know the size of your ball.
I personally like having both methods available. Different situations call for different approaches.
Ready for the Next Step?
A simple 4-division may seem basic, but don't underestimate it. You can create some beautiful ornaments using nothing more than these four sections. This is especially useful if you like to recreate vintage satin, sequined, and beaded ornaments, as the satin-wrapped balls are very hard to find these days.
More importantly, this exercise teaches you several fundamental skills you'll use again and again.
If you're just beginning your Kimekomi journey, this is the perfect place to start.
Watch the video tutorial above to see both methods demonstrated step-by-step, and then try marking your own foam ball.
And remember: aim for accuracy, but don't drive yourself crazy trying to make every line absolutely perfect. The goal is to learn the skill and enjoy making something beautiful.
