What is the Shape Builder tool?

The Shape Builder tool is similar to Pathfinder, in that it allows you to combine shapes to create new paths, but it gives you a little more control in the way those shapes come together to form new ones.

How does it work?

1. First select the two (or more) shapes you want to combine
2. Select the Shape Builder tool. It will divide up all the different intersections of your two shapes
3. Click and drag over divided shapes you want to merge
1. Hold at the alt or option key if you want to subtract or remove those shapes

This allows you to create and work with more complex shapes and designs. Let's go over some examples so you can see how the above steps actually work.

Making a heart

First, make a rectangle

Using the direct selection tool, select the top two points of the rectangle. Using the live corner widgets that appear, round out the top of the rectangle by clicking one of the widgets (while both are still selected) and dragging.

Switch back to the selection tool and rotate the shape 45 degrees counterclockwise by holding the shift key while clicking and dragging. Rotating objects while holding the shift key will rotate the object in increments of 45 degrees

With your object still selected, click on the Reflect tool. If you don't see it in the toolbar, click and hold the Rotate tool (or right click it) and a menu will appear allowing you to select the Reflect tool.

Hold the alt or option key and click on the bottom corner anchor point. This is how you select the axis across which the object will be reflected.

A menu will appear giving you options for how you want to reflect your object. Make sure "Vertical" is selected and click "Copy." If you click "OK" it will reflect your selected object instead of duplicating it and reflecting the copy.

In my case, the heart looks a little wonky, so I will click on the newly reflected copy, hold shift and tap the left arrow key to move it to the left until I like how the top of the heart looks. The overall shape will look less heart-like than it did a moment ago.

Now the good part. Using the selection tool, select both shapes.

Click on the Shape Builder Tool

Now when you hover over sections of your objects, they will fill with a grey mesh and your cursor will look like an arrow with a plus sign next to it. If you hold the alt or option key, your cursor will look like an arrow with a minus sign next to it.

Hold the alt or option key and click on the overhanging sections, which will disappear.

Finish the heart by merging the three divided shapes by clicking and dragging (do not hold alt/option this time).

You now have your heart shape!

Making a Logo

This example will have less detail and go a lot faster. I'm going to reveal how to make a simple logo based on mine (you can see I used this process to separate "Mulberry Moons" from the circle "moons" behind it).

Draw two circles that are different sizes and increase the stroke size a bit

Highlight both circles and expand the strokes (from the Object menu). This will turn strokes into filled shapes.

Offset the path by going to Object > Path > Offset path and inputting a small offset (the number depends on what your canvas settings are) where the new path is about the same width as the original path like the picture.

1. In this example, Joins don't matter, but if you're doing this on text, I recommend playing with the join and miter limit until you get something that looks nice. I usually use Round Joins.

Rubber band select all your objects and you'll see a lot of paths. We're going to use them to create a gap between the intersecting points of the two circles.

Select the Shape Builder tool and zoom in if you need to (it really helps a lot)
Hold alt/option and click on the sections we need to remove. This is pretty much all of the outer path and a few key points of the inner path.

Merge the remaining paths.

Conclusion

I used this tool to create a face using almost nothing but basic shapes and the Shape Builder tool. Give it a try and see what you can come up with. It's a great place to start making more complex shapes from basic ones and it helps you to get creative when working with vector graphics.