Compound path vs grouping: pancakes & donuts help you "get" them

To truly understand using and creating designs in Silhouette Studio software, you need to have a good understanding of Groupings and Compound Paths — how they are the same, how they are different and how they respond differently to modifications. You may hear these words a lot but be confused by what they mean or how to work with them. I have a sure-fire method for teaching you the difference between a grouping and a compound path in a way that’s very easy to remember. I’ll give you lots of examples of why you need to know and show you why when you weld sometimes the middles of your shapes “disappear.”

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Similarities and differences

If you have 2 sets of 2 circles each, one a group of 2 circles, the other a compound path, they will look the same when not filled with color and will cut exactly the same.

But when you fill them with color or try to manipulate the pieces, they act differently.

Why is that? That’s the question this lesson will answer.

An easy word picture: Pancakes and Donuts

In teaching about groupings and compound paths, I find that as an abstract concept it’s difficult to grasp. So, I came up with a simple analogy to explain it. I can’t tell you how many times I have literally seen the light bulb come on for my students when I use this word picture. Just be warned: don’t read it when you’re hungry ‘cuz it involved pancakes and donuts.

Grouping (pancakes)

Let’s say you decide to fix pancakes for breakfast. You put one on your plate and you stack a slightly smaller one on top of it. Even though it’s 1 stack, it is still 2 pancakes. They are 2 solid pieces of yummy goodness sitting on top of one another. You can take your plate to another room, move the pancakes to another plate, or put them in the fridge. You can even nibble around the edges making them smaller. They are still 2 different pancakes. If you look at them from the table level, the stack is 2 pancakes tall.

This is what grouped images are like. You can take 2 images and group them together, which allows you to move them around the drawing area together and resize them together. But they remain separate images even though they are temporarily combined. If you fill them with color, they will both fill, because they are 2 separate images sitting on top of one another. The middle does not have a hole, as you can see in the pic above. Here’s what they’d look like if you could see them from the side in Silhouette Studio.

Compound Path (donuts)

Let’s say you decide to have donuts for breakfast instead of pancakes. So, you hop in your car and drive to the donut shop to pick some up. Yes, some, not just 1 – don’t judge. But let’s just look at 1 for now. A donut it is just one thing with a hole in the middle, not 2 separate things. At some point, the middle was cut out and sold to someone else as a donut hole (unless you buy that too ????). If you look at the donut you see an outer circle and an inner circle and an empty middle. Even though you see 2 circles, they are the inner and outer edges of just 1 donut. If you look at it from the side, it’s just 1 donut tall.

This is what compound paths are like. You don’t have 2 separate shapes. You have a single shape with 2 edges — inner and outer. That means you have a hole in the middle. The 2 circles are considered one line, even if they don’t touch. A shape in a compound path has holes when you fill it with color, as you can see above. If you were able to look at it from the side in the software, you’d just see 1 level.

Text is both

It is important to know that text is both. Letters are grouped together in a word or phrase, but some individual letters are a compound path. For example, if I type the word “love,” it’s a grouping of 4 letters and the letters “o” and “e” are each a compound path. Notice that the bounding box goes around all 4 letters, as it would with any set of grouped shapes.

HINT: This is one reason the size of the text box does not equal the size of the word. The text box leaves space for capital letters, letters that dip below the line, subscript, etc. That space is a part of the grouping.

If you want to remove the middle of a letter, you first have ungroup the word or phrase (even a single letter). Notice the boxes around each letter now.

I could then release the compound path on the letter “o” and remove the inner circle…

…and put a shape there instead.

Notice the heart is a different color. That tells me it’s a separate piece. It’s a stack of pancakes. If I want it to be see-through (a hole), I need to select both it and the circle and make a compound path. That makes them a donut.

BE WARNED!!!!

When you ungroup text, it becomes an image (as it does with any modification). That means you can no longer edit the text or identify or change the font. For that reason, I always recommend making a copy of the text box first and pulling it off to the side. That way if you need to figure out the font or change the letters or font later, you have what you need. Another option is to make a sticky note (an option added in version 4) with the name and size of the font.

Why is all this important?

There are many times in working with images in the Silhouette Studio software when you need to know the difference between a grouping and a compound path.

In breaking designs into pieces

–If you’re trying separate a design into pieces, sometimes the ungroup option is grayed out. That’s because it’s a compound path, not a grouping.

–Some of the designs you get in the Silhouette Design Store or from other sources are compound paths, some are grouped images, some are a combination. It depends on the design and the designer.

–Removing pieces by releasing a compound path is easier, quicker and more accurate than using the eraser or knife.

–Tracing creates compound paths, so to break a traced image into pieces you would need to release the compound path.

In the way the fill looks

–If you combine parts of a design and they don’t look like you expect (don’t have holes in the middle when you fill with color), it’s because you need to create a compound path instead of a grouping.

–What looks like a hole in a design often isn’t. Instead, it’s a separate piece filled with white and grouped with the main image. This can affect print and cut projects and mock-ups you are trying to make. An easy way to see if this is the case is to pull the image off to the side of the mat in the drawing area, or simply overlap it in front of another shape. If you can see through it, it’s a compound path.

–To keep the scale of a pattern the same in different shapes (or different letters of a word), they need to all be in a compound path.

HINT: You can make them a compound path and fill with the pattern and then release the compound path. When you do it this way, the scale stays the same even after you release. Just remember that if you do it with text it will become an image, even if you regroup or remake the compound path.

In the cutting process

–A grouping works differently than a compound path on Cut vs. Cut Edge.

–Compound paths are easier for the software and machine to process when cutting.

In point editing

–Releasing the compound path to work with just 1 section speeds up the process.

–Images must be in the same compound path to join them with point editing.

In using Modify options

–All Modify options work differently with a grouping vs. a compound path. Because you’re starting with different things, you get different results.

For example…

This is why when you weld sometimes your inner pieces “disappear.” If the parts are grouped (or even just a separate piece sitting on one another), an inner piece is completely absorbed into the outer piece. With a compound path, it isn’t.

Let’s talk the breakfast analogy a step further here. Pretend you’ve poured a pancake into your pan and let it sit for just a moment. You realize there’s only a little batter left in your mixing bowl, so you pour it in also right beside your pancake. But since your pan is small, the second pancake runs into the first one. The 2 join together into 1 odd-shaped pancake — a circle with a growth on one side. You’ve created a single piece that you can’t really separate into 2 circles any longer. You may not even be able to tell where the outer edge of the original one was.

That’s normal welding. It joins 2 shapes into a single shape and erases all lines where the shapes overlap. The only lines you see are at the outermost edges. That’s usually what we want, which is why we weld in the first place.

Back up a step now…

Let’s say you so you pour the second pancake right on top of the first. Because you let the first one sit a bit first, its shape is already set. When you pour the second one on, it’s absorbed into the first. Pouring it didn’t create a hole in the first one — it just made a slightly taller pancake.

That’s what welding is like when you have a small shape sitting on top of a larger one — grouped or not grouped –completely enclosed by it. All the lines of the smaller one are overlapped. In other words, none of those lines fall outside the larger shape. And what does welding do? It erases all the lines except those at the very outside. So the smaller shape “disappears” into the larger.

But with a compound path…

What if you had started with an uncooked donut, which has a hole in the middle? If you put it in the fryer and put another next to it, that wouldn’t remove the hole in the first donut, even if they overlap slightly. Say you plop it in right on top of the first donut. It might attach and obscure part of the hole in the first one, but it won’t completely get absorbed into the first one.

That’s what happens with welding when your shapes are in compound path. If there’s a hole in the middle, like on a letter “o,” it doesn’t go away when you weld. That middle wasn’t really a shape — it was an absence of shape — so there’s nothing to absorb. If part of your second shape covers any or all of the hole, then you will see a change in the hole. In that case, you’re adding solid mass into that area.

Ways to group and ungroup

—Icons in quick access toolbar along the top

–Object drop down menu

—Right click menu

—Keyboard shortcuts

• CTRL+g (Windows) or CMD+g (Mac) to group

• CTRL+SHIFT+g (Windows) or CMD+SHIFT+g (Mac) to ungroup

Sometimes you have to ungroup more than once on a design. You can keep doing it until the option is no longer available. Then you’re at the point of working with any compound paths.

Ways to make and release compound paths

–The Modify panel