Masking out sections of a job


I’m just beginning my exploration of Luban, and haven’t been able to find any documentation on this subject, so would appreciate any guidance that you might offer.

I’m laser cutting through some 3mm plywood using an SVG, and there is a small section that didn’t cut all the way through. I would like to be able to mask out the section of the job and just re-run that small part rather than the whole job again. It would seem that the “Mask” feature might be intended for just this, however I’ve not figured out how to employ it. I’ve tried creating a shape to mask out the the section that I’m interested in, but when I click on the “Mask” button, it just keeps saying "Please select a vector and an image at the same time.

Any tips?

Thanks for your time!

EDIT: if it’s not clear, I’m trying to re-cut just the one single gear wheel.

Not so familiar with Luban either but you could simply untag the other pieces or make a new process with the big gear and untag the old process.
Then you could generate the gcode with your new process.

Appreciate you taking the time to respond!

I’m not entirely certain what you mean by "untag the other pieces. I realise, however, that my description might be unclear. The “part4.svg” imported image contains the three small gears and one large gear, however I was hoping that there was a way to mask out two of the small gears plus the large one such that I could re-cut just one of the small gears.

If I were to edit the SVG and re-import, then I run the risk of running into problems with Luban not correctly scaling the imported SVG (which happens regularly and is well documented both here in the forums and on github), plus the challenge making sure the alignment is exact and precise would also be a problem.

All of this leads me back to the question: is it possible to mask out part of the project such that it will only recut a small portion of the vector.


SVG have no scale. They do have a bounding box. Editing and removing objects from the SVG will not change the bounding box, so the scale won’t change. I do this all the time with Illustrator.


If you look through the forums here, there are plenty of other people complaining about Luban failing to import SVG files at the correct scale (e.g., Scaling SVG for laser cutting, plus others but I can only include two links in a post). Also, as I mentioned, there is a documented defect on the github page. So this is a relatively well-know issue.


Like I said, SVG has no scale in Luban. Luban always maximizes the imported SVG to a large size. You have to know the size of the bounding (crop) box of the SVG (which all SVGs have) and set Luban to those that size. When you imported your SVG initially you just have set a size?! Edit out those objects you don’t want, reimport and set that same size. The remaining object(s) will be in the same position.

1 Like

Thanks for taking the time to reply, but I don’t understand how this helps solve the problem. Plus I don’t understand why you’re ignoring all of the other reports of problems with this behaviour.

I have an SVG that I imported and cut at whatever scale Luban decided to use by default. I did not select a size. If I re-import, I have to somehow figure out the precise size of the portion of the vector in question, match it precisely, then line it up precisely. None of that seems practical to me. Per the original question, is it not possible just to mask out a portion of the already-imported image? Especially when there appears to me a menu item for this purpose?

Then that’s a problem. Good luck! I’m all about repeatability. Measure twice cut once.

The simple way, cut it once more, it is not possible with Luban (in a way I know).
I missed that you talk about one image with several objects.

The more complicated way, if you select your image you should be able to see the size and place of this object.
If you import the same object in inkscape and only delete the unwanted models you could export the same model (in its original box) as inkscape svg (not sure about the ending). The scale does not really matter because you could see the old size AND it’s place of the original object.