Merging and Welding Shapes in Inkscape

In this tutorial we'll show you how to unite and exclude your objects in Inkscape.

Making sure your objects are combined correctly is important for laser cutting. Using the Boolean Operations in the Path menu, you'll be able to combine shapes and cut holes in your shapes - resulting in clean, closed paths. We recommend exploring these commands in more depth on your own when you've finished this tutorial.

This is best explained by example. Let’s pretend you’re me and you want your logo cut out on a nice little stand. You’d start with something like this:

Looks pretty good, right? Well, before we get ahead of ourselves, let’s view our design in Outline display mode. I suggest doing this numerous times as you’re designing.

Uh oh, see all those overlapping lines? I see that I have multiple objects all piled on top of one another. I also see a couple stray points, an open contour and a line that isn't connected. I'll to need to fix those issues before I send this file to the laser.

FIXING OPEN CONTOURS

Before I combine my shapes, I want to fix that open contour, or broken path. Using the Edit path by nodes tool (F2), I will select the two nodes that I want to join. In the top tool bar I'll click the Join selected nodes button. 

MERGING SHAPES

Now that I have a continuous path I can merge my shapes. Using the Edit path by nodes tool (F2) again, I'll select all the shapes. In the Path menu, I'll select Union. This will merge all my shapes into one.

DIVIDING/EXCLUDING SHAPES

The example above was pretty simple, because I had already made use of the Exclude tool. It seems like a good time to talk about that. The Division and Exclude tools tool let you reverse one shape out of another while making it all one object. For this example we’ll just look at the only the laser gun.

To start I basically have one gray shape, with white shapes layered on top, where the holes should be. If I  select all and apply black, you’ll see that I don’t really have holes. I need to cut the white shapes from the gray shapes.

Using the Edit path by nodes too (F2), I will select all my shapes. Back up to the Path menu, this time i will select Exclusion. The exclusion tool will cut the white shapes from the gray, creating one shape that i can send to the laser.

I'll view my object in Outline display mode one more time and move my shape. This is to ensure the exclusion tool didn't create any empty objects.

As always, before I upload my design, I'll go through the usual pre-flight checklist:

My file is 2D
My file is built at a 1:1 scale
All my type is outlined
Reversed type have bridges
I have cleaned up all stray points, empty objects and text areas
All my objects are on the same layer