I’ve had problems with Lightburn and its coordinate system since day one. This is the latest. I have a design (Crib war). It has 5 layers. Two are laser and three are carving. I use Cut2d for my design, USG for my carving, and of course Lightburn for my laser. I have my origin in the center of my design (board). What I have done is, I laser the complete design on some cardboard and I use this as a template. This I did I completed just a few mins ago. Everything looks good. Holes, lines and pockets line up perfectly. I used the coordinates of X 150 and y 165 as my origin (center point). I’m using a 3018 CNC. When the template was complete it stopped x150 y165. Now I want to burn out the 6 interier pockets. These openings in the design (cardboard) will be used to line up my template when I start the project on my board. The problem arose when I started the burn, it was 5mm of on the x axis. Why? Nothing was moved, nothing was changed in the design! This is the reason I’m using a template. I have to use it to line up the laser and my carve so that everything will look like it is supposed to. No big deal. As soon as I determined that I was of 5mm, I just jogged the laser over and proceeded from there. I shouldn’t have to do that! I have Lightburn setup so that it uses the “current position” as the starting point. This is just one of the problems I have with Lightburn coordinates!
What is you ‘start from’ and ‘job origin’?
My start from is my current position, which would be X150 y165. Job origin is a joke in Lightburn. I can set it as x150 y165; and when I hit Return to job origin, it goes to the front right. In other words the same as the homing position!
I haven’t experienced any issues with LightBurn’s coordinate systems after fully understanding them. Some of the behaviors and constraints were not intuitive to me initially but all became consistent once my understanding improved.
Is it possible that either your laser is not configured properly with LightBurn or you haven’t fully understood how the coordinate systems work?
If you’re coming from a CNC background some of the concepts in LightBurn are going to be different than what you’re used to which may be throwing things off.
I know that it is probably something on my end. What I can’t understand is why in USG, I have no problems. Lightburn is a different story.
UGS is going to be a different workflow so not apples to apples.
Let’s go through the basics and make sure everything is in shape for you to be successful…
Based on this can I assume you have homing switches? Or how are you establishing your home?
What are the working dimensions of your 3018 CNC?
Can you elaborate on what you mean by origin in this case? There’s no option for center origin in LightBurn so want to make sure I understand what you’re doing for this.
How are you determining what portion of the overall design to burn?
I’m hoping the answers to my other questions will help answer this but my current guess is that it’s because of the combination of using current position with how you’re choosing what portion of the job to run. That will change the relative starting position of the job.
Is there a reason you’re not using Absolute Coords? I think that would get you the exact behavior you expect in a much more predictable way.
I think you’re mixing concepts here. Job origin is the relative anchor point for the job to be run. The relative location of that anchor point is determined by the 3x3 grid below “Start From”. It’s indicated by the green square in the work area. All positions are relative to that point when using Current Position.
I assume you mean “Go to origin” when you reference “Return to job origin”. This origin is completely different than job origin. “Go to origin” will go to a user defined origin that’s arbitrary and set in the Move window. It essentially acts as a user defined origin. It comes into play if you user “User origin” in Start From. This is probably the least intuitive mode and is basically like using current position but with an offset origin. I do not recommend using this unless you’re extremely comfortable with the coordinate systems and have a specific purpose.
Yes, I do have homing switches. Home is set to the lower-left corner. My CNC has a working area of x300 y330. My design is set at x300 y320. My job origin is set to the center of the design in both Cut2d and Lightburn. The interior pockets as I call them, are burned using Lightburn’s layer system. The job origin is set at x150 y165. Before I started the burn of the template, I burned a dot at the job origin x150 y165. This was done as a reference point for any other burns. When I burned the template, I opened up all the layers in Lightburn, made them all visible and set them all to burn. Lightburn did this perfectly. When I wanted to burn the inside pockets, so that I could remove the waste, I closed all the layers except the layer for the inside pockets. I then set it to burn out these pockets starting from my job origin of x150 y165. Lightburn started the burn 5mm to the left of where it made the burn in the previous template. What I noticed; that may be the problem, is that in my design, it is centered perfectly in the work area. Yet, when I did the template, the design was of the center by 10mm. To the right. I notice that in Lightburn it is showing the width of my workspace as 280 mm. When I did my design in Cut2d, I set it at x300 y320. Where the x 280 came from, I don’t know. I think that is the problem. The center point (job origin) is set for at a workspace of x300 y320, yet Lightburn appears to be working with a work area of X 280! The problem could be like you said. I should change the “Start From” to “absolute coordinates”!
As for the job origin. I was always under the impression that you could jog the CNC to any area on the board; Hit “Set Origin” and that would be the origin until such time it is changed! I have tried that in Lightburn, and it doesn’t work.
Right now, I’m looking at Lightburn on my PC. This is what I see. It shows X 148.759 Y 164.750. Width 280.295 Height 320.517. Job origin is set to the center. Start from is set to “Current Position”. This is the one I don’t understand. Get Position, is showing X -299 Y -319 Z -1. The laser is homed at the lower-left corner. Move to position shows X150 Y165. If I hit go, the laser goes to that position. How is that even possible? When it is showing that it is parked at X -299 Y -319.
Clear as mud! I’m doing something wrong. It sure would be nice to figure out what that is. I like Lightburn. It doesn’t like me!
Thanks for your trouble.
Let’s address this first as it can account for a lot of the unpredictability of coordiantes. This is indicating that you’re working in a negative coordinate system. LightBurn, and all laser systems essentially, want to work in a positive coordinate space. This is why there’s a disconnect between your workspace coordinates in LightBurn and actual reported position.
Check here for information about negative coordinates and how to deal with them:
Common Grbl Setups - LightBurn Software Documentation
Once sorted, this will give you direct correlation between LightBurn workspace coordinates and laser coordinates. This is also essential for using Absolute Coords.
Now I’d like to hit on a few things that you said that I either don’t understand or indicate a potential understanding discrepancy.
Can you explain how you’ve set the center of the design as the job origin?
Are you referring to the settings in the Laser window?
How are you setting job origin to a coordinate? There’s no direct way to do this in LightBurn that I’m aware of so I want to understand what it is that you’re doing so I can correlate it to what you’re actually doing.
When you say close the layers, how are you doing this? Are these in different projects or perhaps you’re disabling the Output?
This is easy to confirm. Can you take a screenshot of your Device Settings page?
In the way you’re working it seems to me this would be actually a better fit. That way what you see on screen is what you’ll get in the burn. You can get there using current position but the right conditions need to be in place for that.
Again, job origin and User Origin (which is set from “Set Origin”) are two completely different things which is potentially a source of some of the unexpected behaviors. Job origin is what is set from the 3x3 dot arrangement in Laser window. User origin is an actual coordinate.
Here is the screen shot. Hope it works. I’m using two computers. A mac and a pc. The screenshot is from the pc. Yes, I am using the settings in the laser window. I’m probably using the wrong term in setting the origin. I send the laser to the center of the design X 150 Y 165. That is the point that I start my burn from. I do the same for my carving in USG. I have 6 layers that I work with. I disable the output on the ones that I do not want to work with. I case you are wondering, I’m working on a crib board. Its called crib war. I have 6 layers. The outside pockets, the inside pockets and the holes are carved with USG. The lines and script are lasered. Each layer is done separetly. They have to all line up perfectly with each other in order to look proper. That is why it so important to start each layer form the same location. That is why I make a template from cardboard with all the layers etched on it. I than dry carve or use a low laser power level to make sure it is carving or burning in the right spot. If it isn’t, I than jog the router or laser into a position that will work. I do this for every layer. One mm right or left, or up and down makes a big difference on how the project will look. I generally don’t have a problem with the pockets. Its the lines, the script and the holes (1079 total) that have to be perfect. Amen!
Based your screenshot I can’t see where the workspace is showing as 280 mm. Can you point out what you’re looking at?
Okay. I think I may have identified the specific issue with the starting point shifting on some layers.
You’re using “Cut Selected Graphics” and “Use Selection Origin” while using Current Position. I think what might be happening is that the particular objects on the Line layer (or whatever layer you’re noticing is off) do not have the same center. Keep in mind that it’s going to reference off the center of all the selected objects.
You should be able to see the job center change when you change your selections. The green square on the workspace represents your job origin position. When you change your setup to burn that layer I’m going to guess that it shifts 5 mm on the X axis from your previous selection. It may be hard to see when zoomed out. If you zoom in on the green dot it should be more apparent.
The width measurement that I’m referring to is on the top left of the screen shot. I believe its part of the tool bar. Width 280.295 and height 320.517
Got you. The width indicator shows you measured width of all selected shapes. So the difference between the right most point of your selections and the left most point. If you select all components of your design it should be the full width of your entire design.
Does the measured width of the design in LightBurn match what you have in Cut2D?
thanks. Yes it does. I think what happened is this. In cut2d, in order to establish a tool path for my outside pockets, I had to draw a line around the outside of my design. When I exported the design to Lightburn, that line was around the outside. When I went to lazer the template, the laser would hit the limit switches on the x axis. I therefore deleted the line, thus Lightburn is not calculating the total width.
If I replace that border; I think that will solve my problem!
That should resolve the width discrepancy so think you’re onto something there. If it wasn’t there when you burned the various layers I don’t think it will contribute, necessarily, to the specific issue you saw with the shifting of the one layer.
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