How to combine shapes in *Inkscape* for laser cutting with Ponoko

In three easy steps

Two weeks ago I posted a video tutorial for combining shapes in Illustrator for laser cutting, and I wanted to make sure that our large number of Inkscape users had the same technique available to them…

If you’ve watched the Illustrator video, you may experience a sense of deja vu – the main difference here in what commands to use in Inkscape, and where they can be found.

Below is a transcript of the video:

Hi – this is Josh from Ponoko – and today I want to show you how to combine shapes in Inkscape for laser cutting.

To do this, we’ll be using two key menu commands:

* the first is Path > Combine
* the second is Path > Union

Before we look at this process in greater detail, lets check out an example of shapes in Illustrator which have been combined incorrectly for laser cutting with Ponoko.

At first glance, this looks perfect for laser cutting. There is a thin blue line which traces around the letters on the top, and a rectangular base on the bottom. However – if we change our view mode using View > Display Mode > Outline – you can see that all is not what it seems.

This ‘Outline View’ reveals the true vector content of a file – and lets us know what will actually be made. In this case, what it has revealed is that these letters and this rectangle are not truly connected.

What I have done instead is place white fills over the blue lines in my design that I do not want cut out – which unfortunately would not have worked. When it comes to cutting lines and vector engraving lines, the laser cutter will cut or engrave them anywhere they are present in the design – even if they are covered by something else. The white fills I placed over these cutting lines would be ignored, and the lines underneath them would still be cut.

So let’s combine these shapes correctly.

The first thing we do is select all of the shapes we want to combine together. We then use the Path > Combine command – which combines these shapes into a single unit.

Finally, we use the Path > Union command to turn all of these separate shapes into a single path running around the outside of them, and to remove all the lines which would otherwise separate them.

Now when we change to View > Display Mode > Outline, we can see that these letters and the rectangle below are truly a single vector object. Once again, this a true representation of what will be laser cut – and this time it’s what we want.

Let’s go through this process one last time. We’ll open a new Ponoko template – and create a collection of overlapping shapes which are formatted for laser cutting with Ponoko…

So now we have something vaguely arty – let’s turn it into a single object for laser cutting. First, we’ll select all the shapes that we’ve laid over each other. Now we use the Path > Combine command, followed by the Path > Union command.

All of these shapes have now been combined into a single object ready for laser cutting with Ponoko. We’ll do a final double check by using the View > Display Mode > Outline command, and it’s definitely correct.

So that’s all there is to it. I hope this technique might be helpful to you in the future – for making new exciting projects with Ponoko.


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