Perfectly aligning a complex Passthrough Slot Design

Hey GF Community,

I am attempting to create, engrave and cut out an 18" Circle Map (of any city that the client chooses) on my GF Pro!
(will attach dropbox file link of current project) (Adobe Illustrator)

In my mind, the best way to create this file was to:
– make it to size in AI
– convert to SVG (PNG -> SVG via Advanced Image Trace)
– split the map and the circle outline evenly down the middle at 9"
(I have had great success with this in the past on simpler files where there is dead space, but a lot of the city maps have several roadways I am splitting)
– add a score line at 0", 9", 18" (so you can utilize that for alignment )
– Group the sides into:
Layer 1 (score lines), Layer 2 (left map), Layer 3 (left circle half), Layer 4 (right map), Layer 5 (right circle half)
– Make map and circle halves different colors (4 colors total)
– Rotate 90 degrees to the right, and save in AI as .SVG so it can digitally just be slid up and down on the GFUI with no X Axis movement necessary (as you leave the material positioned on the ride side of the machine and move straight up)

Issues I am running into:
– when I erase, I notice the slightest bump in the design when zooming in on AI at

1000% to check for alignment.
– When I overlap the designs even the slightest, the GFUI seems to read that as a “no engrave area” creating an UNEGRAVED LINE directly down the middle of my design at the 9" point where I digitally split it

Any and all help is appreciated as I am running the design on:
– 20" * 20" 1/4" Birch Plywood
– spray painted and masking taped with 12" JDS Tape to prevent burn
1000/70%/195lpi and the designs are taking at least 1.5hours for each side, resulting in over 3hours for each piece…
*** (any recommendation on how to speed up design time is certainly welcome as well!)

Support can’t help with design questions, so I’ve moved this to a more appropriate forum. They’ll still have to check in now that a support ticket has been created.

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That does look pretty complex, and your ideas are sound.

If you haven’t been selected for the Passthrough Beta project (which closed to volunteers a couple of weeks ago) then your method should work out pretty well, although it’s going to be very difficult to match across that many cuts in the design perfectly. Make sure you are anchoring the material against the side of the tray to keep it from rotating when you slide it.

Matter of fact…there’s a tutorial on doing it in Illustrator here…be sure to follow the notes at the bottom closely, they help the most.

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Have definitely been anchoring the material to the right side of the tray and have used the home comb holders as well to keep the material flat.

I have found that even on the slightest measurements it can look off and is so frustrating.

Also, with a file this long, my internet seems to time out so the best way to get back to original origin is to take a screenshot of the X, Y, W, H and plug those numbers in then scroll it down 9 inches, test at low power then go from there.

But…low power does add up and makes a darker indent as well…

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There’s a lot to get into here and I’m not sure I understand it all. But I do have two thoughts:

First off, are you aware there’s a passthrough auto-alignment feature coming soon? It looks like the window for this beta cycle has closed, but keep your eyes on that thread in case more opportunities come up. Then, in regards to this:

If you are starting with a bitmap image, and you intend to engrave it, I would skip the trace entirely. This has the benefit of “what you see is what you get”, and avoids such issues as:

  1. Overlapping objects erasing each other (as you are experiencing)
  2. Having to do the right boolean operation to “knock out” parts of a shape
  3. Glowforge misinterpreting your SVG (such as even-odd fill rules, etc.)

In fact, I take this to 11. Even if I’m starting with a vector, I always rasterize anything I intend to engrave. This also gives you the opportunity to make one big engrave instead of separate steps, which may be faster depending on what shape it is and how much is empty space.

Thanks for the heads up! The window to apply for beta has closed, but I went ahead and applied for the passthrough auto-alignment anyways!

I download a high quality PNG map from SnazzyMaps then Trace, but you are right, I am almost doing it backwards as the high quality PNG is clear enough to work!

Would you recommend that I make the bitmap image to size then crop the image at
0" - 9" then 9.001" - 18" ?

Thanks for taking it to 11 @chris1 !

I have no advice on splitting the image, I’ve never tried to do a two piece engrave.

There are tutorials on splitting for passthrough in the Tips and Tricks forum.

Self-taught on AI, so I am always learning, but it seems to me the most prevalent way to split an image is to erase it, but with such a complex design as road maps, even taking the smallest fraction out of the design can show a bump in the roads, pun fully intended.
Is there a recommended way to split an image without removing any of the image?
(Thank you for your continued help)

There are ways to handle that. In Inkscape, it’s called “cut path” where the intersection creates a new node so existing path trajectories are preserved.


I’ve done complex passthrough cuts before using snapmarks (I’m not sure if those are available to everyone or not). You split the image and keep a pair of snapmarks on each copy in the same position. The downside is you do lose some of the cut area, but I found it to be very accurate.

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Here’s how to do it with snapmarks in Inkscape.

Doesn’t help with AI, however…

I use illustrator as well. You can do it using pathfinder “outline” which can get clunky because it tends to break all line joins making the cut take longer on the glowforge, or you can use a plugin by rj-graffix that gives a better cutting function.

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