No it came from OnShape, but once the paths are joined via AI there is no excuse for the GFUI to not treat it as a continuous path. How would it even know? Unless you think there is some weird thing where the paths are separate entities added in a non-geometric order to the the path object. I guess I can look at the SVG code to see if it is a single path in order of points.
No, not that, but Iāve noticed that some of the problems with separate segments actually originate in the CAD program thatās doing the exporting.
Iāve never used Onshape, but Iāve seen it in some of the others - Fusion 360 does it - but only intermittently. Itās not something actually caused by the GF software. (And we canāt expect Glowforge to join our lines for usā¦they might do it wrong. Most of the mechanical methods for joining paths automatically do a terrible job of interpretation.)
So I just put up with a wandering beam path. Itās really not an issue from a results standpoint, it just gets freaky to watch sometimes.
Just curiosity at this pointā¦ (but I also havenāt had a chance to do testing on that aspect ā¦thereās been too much other stuff going onā¦)
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I would suspect that you have some end-point nodes in the middle of your path. If you select the node where the motion planning shifted and you move it, you probably only drag one side of the line, because there are actually two nodes in the same space.
In inkscape, you can select both overlapping nodes (click and drag a rectangle) and join them to restore path continuity.
The trapped smokeā¦ cannot think of any cure for that, fan on while you are removing the piece seems like it would only help marginally. But I have no idea of how strong the fans really are.
Okayā¦ wrote responses as I was reading, so I see that the split paths was already consideredā¦ @henryhbk, any chance you could pop the SVG up on here? I am also curious as to how this happened.
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I havenāt taken the honeycomb out of the tray, but if it could be shimmed up a mm or so that would open an airflow pathway under the honeycomb that would let the exhaust pull it all out through the exposed honeycomb holes.
My PRU is 3000 miles away so I canāt check to see if this is possible though. Iād know if I had cleaned it before 
I was thinking maybe a simple pin bed would work, if the pins just stick up a mm or so above the honeycomb.
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Thanks. I am very interested to hear the story behind this one from the Glowforge team. There were two non-joined nodes, which I had thought were the cause of this. But only one of those was at a point that the path broke, and it broke in a LOT more than two places.
The two parts even look to be cloned from one another, but the machine broke at different points in the path on each one!
I looked at it too, and found that each of the paths was un-joined, at the locations shown belowā¦
Had to change the stroke size to .01 pt and zoom all the way in to find themā¦
So far, Iāve seen the Glowforge interface treat unclosed paths as if they are created from discrete segments, and it optimizes the travel path it takes. (It has itās own Wild Willy Wander thing goingā¦whatever that thing is called.)
This file looks consistent with that.
Anyway, whenever I see it go off on a walkabout, I check my files for un-closed paths. (Thatās if Iām planning to share them, if itās just one of my own files I usually just shrug and āWhoops! Left one open somewhere.ā since it doesnāt affect the results, just how it gets there.)
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So weird since I selected the entire outside path (with a box drag) and selected cmd-J and it threw no error. (and yes they are mirrors of each other from OnShape, so repeated twice). The second image is more concerning since those donāt quite line up! WTF? On this job it had no effect other than being noticeable.
yeah, weird right?
Yeah, never works consistently for me either. 
Doesnāt throw the error, and worse, it doesnāt join the lines. The only way I found that works for sure is changing the stroke size, zooming way in, and checking the stupid thing. Itās tedious and ridiculous for complex files though, since the GFUI will cut it anyway, so I donāt mess with it muchā¦itās a waste of time.
Iāve seen that too sometimes, with some of the 3D stuff from F360.
(I have no doubt itās because i didnāt quite join something properly somewhere, but itās really hard to find those sometimes*.)
*Particularly since I donāt know what the heck Iām doing yet. 
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It seems to act perfectly if everything is a straight line, but gets funky the minute there is a fillet on anythingā¦
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Yup! Iāve seen it mainly with curved lines tooā¦ (Fillets are a beeyatch in Rhinoā¦they have a known issue on those coming out wonky in a mesh file.) āSā curves are bad too in F360, or curves with a lot of switch-backs.
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Weāre definitely looking at ways to reduce āfugitive emissionsā - that is, bits of smoke or other aromas that sneak out.
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Since you expressed not knowing, and are on the tutorial team, going to take a little while to spread what I know about it.
Using Inkscape. Look at the way the nodes are represented:
See how the sharp corner has a non-stroke diamond, instead of a stroke square?
That means there are two nodes there. So, zoom in.
Sure enough!
How to fix it? Cakewalk.
Select both nodes (click and drag a rectangle over the node is easiest), then click on the Join Nodes button:
And you are back to normal, one node, and continuous line.
Nowā¦ if the nodes are all spaced pretty far apart, you can get away with just doing a select all (while in the node tool) and then hit Join Nodes. It does work in this specific case. But I have had some complicated designs get incredibly messed up because of overlapping lines which happened to have some nodes near enough for the tool to do things I didnāt want it to do. So I caution on the purposeful selection.
I am curious if the path behavior changes with the nodes properly joined in those spaces.
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2D vector Iām fairly familiar withā¦3D Iām learning. 
I need to go take a look at Illustrator and see if it has one of those little join buttons like Inkscape doesā¦I generally just right click and select the Join button and that doesnāt work the same way. (Itās not always effective, and thatās usually because you have selected more than two nodes to join in your operation.) For instance, you always get orphan nodes if you delete a segment out of a closed shape, and those have to be deleted if you want to use the Join tool on the ends. Lot of work, and very tough on the eyes.
One of the things that has absolutely thrilled me about the Glowforge interface, was that we donāt have to join the paths in order to get an excellent cut. It really does just as good a job at picking up all of the segments, even if itās not in what I would consider to be a logical order. They are optimizing the travel path for something, I just donāt know what it is.
Best part? There is no overburn when it does. (Critical.)
So I generally donāt care if it wants to wander around a bitā¦Iām just glad I donāt have to join the paths in Illustrator. (Itās a pain in the tush.)
But anyway, back to the original pointā¦if you guys see the cut start to wander all over the place in the Preview instead of following along the pathā¦just check to see if your shapes are closed. You donāt even have to cut it, you can see it in the Preview.
I think that is what is causing the laser to meander. Itās optimizing segments.
(Could be wrong thoughā¦ itsā been known to happen.) 
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Iām interested in how many people wait & watch the preview? I just punch the button 
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Guilty. 
(But we could use it if we wanted toā¦)
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with incredibly rare exceptions, I too just punch the button.
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I donāt punch the button. I lovingly press the button, ever so delicately. 
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I usually stab it with a stick from across the desk!
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