Alignment / Fisheye help

[ursula.sadiq]

So, I made and scored a 1" grid on my GF basic from a SVG file onto proof-grade draftboard You can see the upload lined up the grid exactly on the GF UI Ruler.

After cutting, the Y axis lines up well across the whole piece. Yay.

However, I’m getting some significant fisheying in the X (well, signficant to me at least) :-/

Also a slight shift to the right even in the center.

My question is: what, if anything, can I do to improve the fisheye-ing and/or shift?

Thanks!

[Jules]

@ursula.sadiq

what, if anything, can I do to improve the fisheye-ing and/or shift?

@cynd11 has a great method for improving the current placement situation

A way to improve object placement

Here is the method I use to compensate for the slight offset I currently experience with object placement. This method will probably be obsolete when precision alignment is available but in the meantime it can help if you want exact (or at least extremely close) placement of artwork on the bed. Using this file: [image] Upload it to the GFUI. Set up a score. Attach a piece of graph paper (here I’m using 1 inch grid divided into tenths) to a piece of card stock and measure the thickness w…

Other than that, we can’t really do anything right now to improve it - there are changes to the alignment coming for everyone that will make that better once they are rolled out, but it’s something that Glowforge has to do on their end.

[julybighouse]

Out of curiosity, can you measure the scored grid? Do you have 1" x 1" squares across the whole thing?

I’d just like to know if the GF itself is either not displaying or printing properly.

[palmercr]

I think it always prints the design accurately. It is the camera view that is not accurate.

[Jules]

Correct so far. (Excluding accidental export in a different size.)

[markwal]

You may also be interested in this post:

Camera Alignment

This is extremely correct. A very small vertical distance will create a very large horizontal offset in the preview. We’ve never seen this happen. Given the way the hardware works, I believe it’s unlikely - if it moves at all, it’s going to fall off. In manufacturing, ever part has a tolerance. Machine-to-machine variation is calibrated out at the factory, though. Indeed. It’s easy to obtain much larger or smaller values depending on the height error. (There are other sources of error…

I think the upshot is that since you have good horizontal lines you’re probably as close as it’s gonna get for now.

[jason.fuller0]

I’ve also observed times where the original preview matches exactly placement on the material and the postview is shifted.

[palmercr]

Seems like it forgets the height setting, or perhaps it adjusts it when it takes the measurement for focus. However that should make it more accurate, not less.

[Jules]

@jason.fuller0

I’ve also observed times where the original preview matches exactly placement on the material and the postview is shifted.

I have too, and my thoughts on it were that it was because the thickness information wasn’t being retained for the second shot, so the focusing could be way off on the after-image.

Haven’t noticed it as much lately, but I’ve been working pretty exclusively with Proofgrade, which would repopulate with the correct thickness when it took the second shot.

(Or they might have fixed it somewhere along the line…not something I’m obsessing over. There have been so many changes over the last few months I gave up keeping up with them a while back … )

[palmercr]

What happens if you refresh the bed image post print? Does it go back to the original view?

[Jules]

Don’t know…haven’t tried it lately.

[ursula.sadiq]

Thanks everyone for the feedback & tips. I’ll just anxiously wait for alignment improvements to roll out.

To answer/confirm some questions:

• yes, it printed the grid at perfectly 1" x 1". The print is accurate to the design.

• I made the grid in Inkscape to be a 1" x 1" grid. The overall rectangle was 10" high and 19" wide.

• I mostly care because I like to flip things over and print on the back, and like things to be centered. And/or print on/over something that already has a design. Or print on precut discs, dogtags, plaques, etc.

• Nobody asked, but the the machine is Level. I double-checked.

• Since I now have a grid “Map” of my offsets, I should be able to work around the shifts, similar to the sighting-a-scope method from @cynd11 . Still looking forward to the day when I won’t have to!

[jason.fuller0]

@ursula.sadiq

I mostly care because I like to flip things over and print on the back, and like things to be centered. And/or print on/over something that already has a design. Or print on precut discs, dogtags, plaques, etc.

If you cut the outlines in something, such as cardboard, then don’t move that material, everything placed inside those lines will give consistent results. Overprinting something otherwise sourced might be a little trickier.

For tags, especially double-sided, I’d just cut the outline in cardboard while ignoring the engrave, then ignore the cut and place the tag in and run the engrave. Will give 100% consistency inside the same batch as long as the cardboard isn’t moved, even for flipping the tags.

[trilo]

That is consistent with the kinds of distortions and inaccuracies we’ve been seeing on our Glowforge Pro.

[Rita]

Thanks for great research and explanations. We are still improving our layout and alignment.
Happy printing!