Seeing how LB 9 point has the (Easy) after it, I’m guessing maybe one day there will be a “(Hard)” 27 point or something coming up that will address this. Usually you can find a happy medium where everything scales but sounds like that isn’t working for you. Maybe try setting the scale with a box that is 50% of the working area.
Yes, a 25 point scaling is planned.
1 Like
I’m dreaming of an “Extra Easy” mode with image recognition.
*ducks away to not get hit by a camera.
But seriously:
It would be so easy if manufacturers provided a .COR file.
3 Likes
If that is able to give me micro level percision, heck, even 0.1mm, I’m willing to do it.
Until you buy a new lens.
That’s what I meant: Ideally, each lens would come with its own .COR file to load in LightBurn.
By the way, they are generated by a separate program (I’ve seen “cor.exe”, “cor2.exe”, and a “CalibrationWizard.exe”).
I always assumed it is a combination of both mirror servo and lens distortion so unique to each machine. But it would be interesting to do lens correction, move both the lens and the correction file to a different machine, and see if it matches. I remember cor and cor2 utility came with ezcad/ ezcad2 and were for adding new lenses, not sure what utility generated the markcfg7 file that also use to come with the ezcad lasers, one for each lens, because ezcad doesn’t use that file. Funny thing though, LB can use it, even though it was ezcad files before LB even supported galvos.
Surely some update on this right…
There’s a known issue on our side, that the Scale values of the lens might not be accurate after the 9-Point Calibration but it can be corrected by running “Calibrate Axes” after the process, as explained by Alboswift in this thread, and here.
In the meantime, we’ve heard other reports about ComMarker’s 250mm lens that it had some non-linear distortion.
As mentioned, we’re aware that LightBurn’s 9-Point calibration doesn’t offer enough test points do undistort this fully throughout the whole workarea. This is more evident when using a longer lens like your 250mm one.
We have plans for an advanced 25-Point calibration, which would add more measure points to improve this. It’s on the roadmap, but we can’t give you a timeline when it will be ready!
If you can get a .cor file from ComMarker, you can load it in the Device Settings here:
@gazinggod, any updates from your side about the previously suggested solutions?
Oh, my problem has always been about the non-linear distortion. I might not have word it correctly. ComMarker has given me a 200 Lens, But the distortion is still too great for the work I’m using it for.
It’s Chinese New Year at the moment, I intend to message them afterwards. Hopefully they will update their software and provide a.COR file for the Lens.
The machine arrived NOV last year and it has mostly been collecting dust due to this error… More than 6 grand just collecting dust…
Seems like ComMarker updated their software with a few different level of multipoint calibration. But it generates a custom .cor file called .gcor not sure if I can just edit the file type and use it in Lightburn or not..
One way to find out.. 
Can you send us said .gcor file?
Upload it to WeTransfer and send us a link, if necessary.
Unfortunately I’m currently overseas. Back on the 20th. Will do the calibration and stuff then.
2 Likes
Ok.. It’s much better.. But still have distortion that is greater than 1mm.
Plus I am not able to do the calibrations, have to ask ComMarker.
Plus plus.. The calibration file will not work in Lightburn..
Please Lightburn.. Implement a 17x17 or even 9x9 calibration
Well.. They said on the 20th March that they will give a.cor file…
But clearly they didn’t understand what that actually means…
So, you managed to import their calibration file? Or is this after you did the LightBurn internal 9-Point calibration?
Did you ensure that the focus height is accurate?
If the results from your image are from the LightBurn internal 9-Point calibration, you might just need to Calibrate the Axis again.
LightBurn can load .cor files even if they were created with a 25-Point calibration. As stated elsewhere, some calibration tools only save the raw measurements in the .COR files.
Other versions convert those into the lookup table that the hardware uses. We only support the ‘hardware lookup table’. More information on this here.
That’s why I previously asked:
One solution would be that ComMarker could export the calibration file in the lookup table format that LightBurn supports. But if the raw data is inaccurate in the first place, that won’t help much.