I’ve been bitterly disappointed with deepnest as it resized shapes and generally was very fragile, but someone recently posted on the GitHub to set your units to mm and scale to 10mm and it works great.
Tried it a number of times now and getting reproducible, accurate results.
Can’t tell you how to make it work with imperial units.
I’ve given Deepnest a try again, but after an hour it’s only found room for 7 out of 100 items, so I canceled it. The processor of my Macbook pro was also going crazy. I have to sort my items manually, just like I always do. It’s a bit annoying but also explains why LightBurn does not want to have anything to do with nesting.
Who said that? We have acknowledged that it is a very difficult problem to solve reasonably. I believe the issue is “when”, as this will require a significant effort. So far, other development work has taken priority, but I don’t recall LightBurn saying we do, “…not want to have anything to do with nesting.” 
… that’s correct, I’ve just been able to skim what a lot of work it takes to get it implemented, so I came to write it. The nesting function and centerline tracing are both very high on my wish list but I am aware that this is only possible when everything else is in place.
Since I managed to stop it changing size, I’ve used it a lot more and found it to be pretty good, with limitations.
Regular-shaped objects are best, as it bounds an irregular one by its furthest extents and won’t put little bits inside large cutouts.
When I’ve got a lot of small, similar objects, I’ve found the matrix option in LB to be just as quick, but if I’m using a file with many small parts, like a building or small machine, it does pretty well.
You can tell it how many processor cores to use.
These are my default settings on my Mac. (ignore the DXF inches settings - I use SVG and so never changed it). It was set to 8 rotations for a specific instance, but normally I have it set to 4.
After reading Bo’s first post to this thread, I went down the rabbit hole and did some Deepnest testing. It is interesting to see that some of the replications of a shape appear to be exact clones but other replications are slightly altered. I used a shape of a very crudely drawn star for my first test. Then I did 100 mm squares. Both showed the same behavior. The difference is so small that it will not matter on our lasers but it is interesting that the replications were not exact.
I’ve been attempting to use deepnest as well. I was having issues where circles inside of circles were getting turned into what looks like a pair of merged ellipses or binoculars. Having exports to inkscape to see if Lightburn export was the problem, I’ve come to find that some circles needed to be converted to path for Deepnest to play well. Still messing around with it, but thought I would put that out there to experiment with converting all to path before putting into Deepnest.
