Cannot get symmetrical shapes no matter what I try

Hello wonderful people, I am hoping I will be able to get some help with this because I’m just about ready to tear out my hair after a long week of trying to figure this out.

I am trying to design and cut out a guitar template that gives me two identical halves when split down the middle.

I used the pen tool to design one half and have tried to mirror, duplicate and flip, even gone into illustrator and tried to do a reflect on the shape but no matter what I do, mirrored, dulicated and flipped, the duplicated shape changes slightly and is not symmetrical. So I cant get them to match.

I initially thought my eyes were playing tricks on me so I cut out a bunch of samples. The mirrored/flipped half does not fit exactly on the standard half. Each side does not sit back in the cut out when flipped either. I’ve attached a bunch of pictures to an imgur album to illustrate things better here:

I’ve made sure the points are aligned perfectly along the X axis as well.

Any help or advise how I can get this working would be appreciated so so much.

Thank you

Your lines on the plywood look very uneven.
Was that just one pass?

Yes the images were one pass. I’ve tried up to 3 passes as well result is the same. I was wondering if it was just slight burn discrepancies myself but I’ve tried 13 different options and the part where it is off is identical in all of them.

Based on a photo/video, it cannot be judged where the problem lies. Sent your LBRN2 File up here and we find the error/solution together.

That makes total sense and I really really appreciate the help.

The file I am working with is attached. The left half is what I made from scratch in lightburn. The points on both sides seem identical but even within the light burn file to my eye I can see the issue. I’m going to sit in a corner and cry if this is some silly silly thing I am overlooking.

Mirror Symmetry Issue.lbrn2 (12.2 KB)

Hi Dimitri, I have copied your halves one at a time, duplicated them and mirrored them. Then I auto-assembled the halves and duplicated them again for comparison. Both of your halves are perfectly symmetrical in my little experiment.

Mirror Symmetry Issue-retur.lbrn2 (14.7 KB)

Thank you so much for you time. I tried something similar with Photoshop and illustrator to check the halves too and in the software they align on top of each other perfectly when overlayed as well. Yet when I burn them they just don’t fit together/align close enough for comfort as you would have seen in my pictures.

I’m really stumped as to what i can do.

This isn’t likely a design or software issue.

This is most likely going to be something mechanical. I’d suggest a full review of your machine to make sure everything is properly assembled. Make sure you have proper tension on belts and that movement is smooth through the entire travel of the machine.

Specifically, I suspect your machine is out of square. If you push the gantry of the machine to the extreme top or bottom do the left and right sides of the machine touch concurrently? Is there a gap on either side when one side touches?


Oh my god. @berainlb you are a shiny golden god! The belts were out of whack and the gantry was no where close to square pulled everything a part and setup again. It’s a cheaper machine so I doubt I’d get it bang on square but its close and the test cut is pretty much perfect now. I will do a more extensive check tomorrow but I’m certain this is it.

Thank you so very much to everyone who assisted!


Can we please have Berain’s title changed from “Community Leader” to “Shiny Golden God”?


Maybe Lightburn staff can add a category.