Testing files before cutting


I ll see many posts about problems on svg/ai files (too many nodes, double lines)…

I won’t have my GF and will normally receive it on february. In the mean time, I prepare many files after reading the great tutorials made by the community (Thanks, Thanks, Thanks again for the amazing work and share!).

But when I see the troubles on files I wonder if some or many of my files maybe have those issues and have to be made again later.

So, as I have no lasercutter to test my projects, does anyone knows sort of virtual tool to simulate laser result? Or any trick to easy detect “Oh, there is maybe a problem on this one”.

For example I thought about using an online laser supplyer like ponoko. with price comparison it could be a way to detect double cut or too many nodes and optimize files.

Have a good day


PS: and maybe the best trick is : VE-RI-FY. But any further trick will be great.


I’m not sure there is one easy answer to your questions, although if you explore the Designing for Laser topic in the Glowforge Tips and Tricks category it should help.

If you have a file that you would like to be checked out to see if you are on the right track, I would be happy to try uploading it to the GFUI and do a critique on it to see where it might need changes. Just upload your SVG here (or send it to me in a private message if you prefer).


You’re right about the category of this topic but I don’t have the choice to put it in Glowforge Tips and Tricks. So I put it here as default option.

Thanks for your help offer. But it’s not for a specific file. As I make many files at this moment with no possibility to try them. I wander if there was a simple way to pre-check or simulate them and avoid some mistakes which needs time to correct when I will have my GF.

Sorry I didn’t make myself clear. I meant that you could try some of the tutorials in the Tips and Tricks section, not that you should post there.

I’d still be happy to run a file for you. As far as I know there is not a simulator, although it has been requested by others.

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And likely a few of us who would be willing to run a test of it for you too. Especially if the material doesn’t matter (if it’s okay to use Baltic Birch or HD MDF underlayment).


I would be happy to try any file in the GFUI and test it out in cardboard. I think that if you gave us a few to work with, we could give you the pointers you need to ensure you have files ready to go when you get the Glowforge. Post them here or PM them.

Ponoko has some good instructions on what is demanded of the file for their services. They can be applied to Glowforge designs, but in the end, the only way to uncover problems at the moment is to load them into the GFUI. There is no on line SVG checker that says you are good to go for a Glowforge, although some folks have thought about writing an Inkscape script that looks for common problems. We had thought having an online sandbox to test designs would be helpful. But we can share our GFUI with invited users, so that might work if you can find someone with a Glowforge.

Before any pre-release went out, the forum explored this problem in depth. No one had a Glowforge to test a file out so it wasn’t quite clear. Eventually the Beta folks helped demo some things and with some clarifications from Glowforge, we figured out what would work and what wouldn’t.

Some pre-flight check list to go over your designs with would be handy with both vector and raster objects requiring specific controls.

Let me take a stab at it off the top of my head for vector-based SVG files.

Vector: try to break your file down into these steps. And this is off the top of my head. I will edit this list as I get corrected by community members or get added suggestions).

  • one color, one operation (cut, engrave, or score)
  • one object, one operation (cut, engrave, or score)
  • either a filled closed shape of one color with no defined stroke to make an engrave
  • or a single path of one color, closed or not with no fill to make cut/score
  • Closed paths can either be engraved or cut/scored in the GFUI but the default behavior is filled engrave, non-filled but defined colored stroke cut/score. Always defaults to cut, but can choose score.
  • use as few nodes as possible
  • join paths to complete a line or make a corner, don’t just put the ends next to each other
  • white is a color, if you don’t want it engraved, unset the fill color totally
  • Overlap filled objects require special attention, the overlapped space may not turn out as you wish
  • you may have to punch out or do a boolean remove/union/difference overlapping shapes to ensure that no hidden closed filled path is under the top object closed filled path.
  • Text/type is treated specially in design programs to allow for editing of text. The text must be converted to paths before sending the file to the Glowforge for processing.
  • Grey scale or percentages of a color fill of vectors do not register in the GFUI. A 70% black color will be treated as black. You can’t control grey scale engraving using a gradient fill in a closed path vector object at the moment.

Ok, that’s it. I’m digging a deep hole here. This doesn’t even touch bitmap prep, placement, sizing and the many ways to treat them in the GFUI.

Best would be to get someone with a Glowforge a file and then see what it needs.


To be clear though, these two go together. You can put objects on top of each other or overlap them. However, the default behavior will be to process them as separate objects so for instance it will engrave the bottom one and then engrave the top one over the full bottom shape thus double engraving the area of the top overlap which is not what people usually want when they’re overlapping objects. For most cases with an overlap or overlay, you’re likely looking to have an island (where the top object isn’t engraved) or where you want to do a dark engrave of the bottom and a light engrave of the top. Without boolean operations you’d get the both operations processed on the “top” one.

Use the booleans to make these single objects so you don’t double up on engraves or cuts or something. There’s a bunch of stuff in the tutorial matrix on how to use booleans in the different design programs depending on what you’re trying to accomplish.


I guess I was writing it in terms of best practices and what to avoid in general rather rather than saying what you can do in a design program and then say why you shouldn’t do it.

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Since it’s a common use case - people want things overlapping or overlaying other things. They just don’t want double engraves or such.

Trouble is it doesn’t make sense to most people until they do it. It’s always a head-scratcher in my classes until I walk through a specific example (I use our makerspace’s logo because there are multiple islands and recesses in it). Once they see how it’s done the light goes on and they’re good to go. But I’ll be that’s got to be one of the top 3 issues people have when first designing for lasers :slight_smile:

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My Latin teacher said, don’t ask why, just ask how and do it. Sage advice for me. I myself like to understand the why behind an instruction or command. The forum is grappling with the difficulty of providing instruction without getting lost in all the different ways the design programs accomplish something, the variety of names for design operations and features among the programs, and how the the GFUI does something. In the end the only advice we can give to folks is spend time learning about designing for the Glowforge. The concepts aren’t difficult (in the sense that understanding quantum tunneling is difficult*) but there are lots of them and it can get complex.

@Jules’s tutorial here would be one of the best places to start in getting the knowledge needed to evaluate your own design. If folks do not understand all this basic terminology, it is very difficult to assist because there is no common vocabulary to talk about design features.

*and before someone launches into a reply that quantum tunneling isn’t all the difficult and here’s how to understand it, recall our purpose here. And I’m as guilty as anyone in complicating and obfuscating issues.


That’s one of the only areas in my life that I gave up trying to understand and just accepted the explanation so I could move on and get the “right” answers for the tests.

It’s really difficult to be an electrical engineer when you don’t believe in quantum energy or things like electron orbit shift (it was here & now it’s there but it was never in between) :smile:

I understand the theory explains what we observe but it doesn’t seem right. So I nodded my head, gave the answers they wanted on the exams and went on with my life.

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although, generally, the best practical advice is good theory

Yes. I’ll never be able to memorize all the use cases of “por” and “para” in Spanish. I’m still trying to crack the nut to be able to figure out which one to use for which verbs. It’s complicated.