Moving Art After Focusing? Is That The Trick?

Hi all - been working with a bunch of different materials. I calibrated the GF Pro and all seems Ok - I think I found the ultimate solution to aligning art on different height materials and wanted to get some input on the following steps (which seemingly work 99.99% great)…

Assuming everything is calibrated and your GF is working great…

  1. Place materials on the crumb tray (or if you need it removed for taller objects)
  2. Upload art
  3. Set focus (this will often make it look like the art has moved from your original print placement)
  4. MOVE ART AGAIN TO PERFECT PLACEMENT (this was what I was missing prior!)

Now, my assumption was that setting focus was setting the art in place too - seemingly, it’s not until you tap “print” and physically start the GF with the white button.

Am I right? Seems that my step 4 was the magic that I was missing.

Thanks in advance to the group. Cheers!

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You definitely need to focus first and then move your artwork around. The closer to center you are the more accurate it will be. Off to the sides it may drift a bit due to to the fish-eye lens.

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In step 3, it’s not your art that’s moving, it’s the camera image behind it that’s “moving” by being scaled smaller or larger. Your art only moves when you move it.

Warning: long explanation incoming.

There’s a camera on the lid of the machine pointing at the crumb tray. It takes a picture of your material, which shows up on the GF application, bordered by some rulers, and you line up artwork with your material that way.

But how does the Glowforge know how big or small to make the camera picture so the rulers are accurate and you’re lining up your artwork with a life-sized image? After all, a 4 inch square of wood will look larger than 4 inches if it’s closer to the camera, and smaller than 4 inches if it’s further away from the camera. That’s just how vision works, right? It can only scale it to show up as 4 inches on your screen if it knows EXACTLY how far away that wood is from the camera.

Since the distance from the camera to the crumb tray is a known number, the only unknown is how thick your material is. If you use Proofgrade materials, the thickness is programmed in. It’s still an approximation, since every piece of wood or plastic varies a little from the next, but it should be pretty close. That means the camera picture will be scaled pretty close to “true to real size”.

But if you put anything else in the machine, it won’t know, and the picture won’t be the right size. If you line up your artwork with that picture, it will print somewhere other than where it shows on your screen… unless you provide the material’s thickness.

And you can do that by measuring it, or asking the Glowforge to measure it. The “Set Focus” button tells the Glowforge to go measure the material height using its laser range finder on the bottom of the print head. If you don’t use the “Set Focus” button before hitting the “Print” button, the first thing it does is go and measure the material height on its own, picking a point near the middle of your design as the place to measure it from. That’s what it means when it says “autofocusing on your material”, the first part of the “preparing” stage before the time for your print pops up.

If the measurement it comes up with is different from the height of the material you had selected, you’ll see everything “shift” on your screen as the camera image is scaled to true size. But if you had already used the “set focus” button before lining up your design with the picture, the image is already scaled, this step of “preparing your print” is skipped, and there will be no shift.

TL;DR: Use the “set focus” button, and then line up your art with the now correctly scaled camera image.

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Thank you for that explanation. Yes, not the art that’s moving but the perspective of it through the new focused image. Got that. Community is definitely worth tapping into for newbies. Appreciate the detailed explanation too. If GF would simply state (unless I missed it) to move your art after focus, I would have saved quite a few draft boards!
Appreciate the confirmation - thank you!

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Welcome to the forum.

Glowforge does give instructions about alignment, but you have to look for it: https://support.glowforge.com/hc/en-us/articles/360033633714

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I have a very different method.
I use paper. I lay down a piece of paper (i use magnets). I will score very lightly (full speed and 6 power) the outside edge of my work. I can then place my material directly over the paper and be sure the art will be exactly where i expect it. I then use the camera just to verify. I use this on almost everything. this really works well for engraving on objects, i simply draw the object in my software, place the artwork where i want it (make sure the object line is a different color) upload the file, place the paper, score the outline of the object, place the object and engrave. this is also great when you have many of the same object to do at one time.

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