Z Offset plugin needs testers

[jens3 11]

I sit corrected, the gcode for the Z offset is in fact in the file, just not where I would expect it to be.

Turns out it is right after the comment  (presumably by Cura) "Layer 1". The problem is, layer 1 is in fact the second layer and the Z offset needs to be applied to the first layer.

[ahoeben 1,948]

Can you upload (the first part) of the gcode file somewhere, so I can have a look?

[jens3 11]

Attached is the heavily edited gcode file for a little square test coupon that I use for setting up things.

 

All routine moves have been edited out with '<snip>' comments.

The gcode file has been cut off after the z offset section.

Z offset was for 200 mm to make it obvious.

Hope that helps!

CCR10_coupon.gcode

[jens3 11]

ahoeben - Any thoughts about the example code I posted ?

[ahoeben 1,948]

I have no idea how this could happen, and I cannot reproduce it.

 

Can you export a project, so I can see all your settings for the current printer?

If you add a new printer, say the Ultimaker Original, and load the same object with default settings and a Z Offset, does the same happen?

Edited April 16, 2018 by ahoeben

[jens3 11]

Most interesting (and strange) ... taking the same object and slicing it in a new copy of the same printer (CR-10) produces the right code. Even taking all of the pre-amble g-code from the old printer and sticking it into the new printer setup results in the proper g-code output.

I do not know what 'exporting a project' is - can you give me a hint on how to do that ?

[jens3 11]

A bit of further info:

The default layer height on a new Ultimaker Original is 0.1 and the resulting g-code is fine'

Leave everything the same but change layer height to 0.2 and the offset is inserted at layer 1 !!! ????

 

Honestly, I am not making this up !!!!  Talk about weird crap !

 

Going back to my original CR10 printer, at a layer height of 0.2 the z height adjustment is inserted at Layer 1, at a layer height of 0.15 the z adjustment is at layer 0 as it is supposed to be.

 

[ahoeben 1,948]

Thanks for looking further into this. I still can't reproduce it though, but I am running what will become Cura 3.3 from source so it could be that the underlying issue has been fixed. I'll try testing with other versions.

 

You can save a project with File -> Save project.

[jens3 11]

The plot thickens and stuff is getting even weirder ....

Ran the same model on Cura 3.3.0 Beta with exactly the same behaviour BUT ran another small item and it produced perfectly fine g-code.

I have attached the saved project file but stuck a .pdf on it to be acceptable to the forum. It is not a .pdf file and the extension needs to be removed!I have one more thing to try and will report if it produces any usable results ....

CCR10_coupon.pdf

Edited April 17, 2018 by jens3

[jens3 11]

The object I was testing on was a square 30mm by 30 mm by 1 mm tall. If I increase he height to 2 mm, the resulting g-code shows the Z offset code at the right place but change the height of the model to 1 mm and the resulting g-code puts the Z offset code at the layer 1 level instead of the layer 0 level.

 

I am taking a wild guess here but maybe the issue is related to the number of layers generated ?  In other words it almost looks as if there needs to be a minimum number of layers before the z offset modification is inserted at the right spot. If there are fewer layers generated than the magic number, the z offset code is inserted at level 1 ......

 

Very curious

[ahoeben 1,948]

Can you test http://files.fieldofview.com/temp/ZOffsetPlugin.curaplugin ?

Download the file and drop it into Cura. Restart Cura, and it should work.

 

Here's what I changed:

https://github.com/fieldOfView/ZOffsetPlugin/commit/5d92f0f2140ab50c4557b47d64e56d4c1db2a68e

Somehow, the first layer can get "mushed into" where the start gcode should be. Now I'm splitting those two if that happens.

Edited April 17, 2018 by ahoeben

[jens3 11]

Can you explain a bit more what file you want me to test ? .... I have no clue what you are talking about.

[ahoeben 1,948]

Sorry, the forum did not make a link out of my url: http://files.fieldofview.com/temp/ZOffsetPlugin.curaplugin

Download the file and drop it into Cura. Restart Cura, and it should work.

[jens3 11]

Hmmm, I have the file but having issues with the 'drop into cura' part.

I am running Ubuntu Linux and cura is an appimage file and not a directory.

[ahoeben 1,948]

I meant "drop it on the running Cura window"

[jens3 11]

Hah !  I was not able to install your fix on 3.2.1 (was unable to remove the previous installed z offset plugin) but managed to install it fine on 3.3.0 beta and it seems to work just fine !!!

 

Thank you very much for your help !

[ataraxis 51]

I fear this plugin doesn't work anymore on FW 5.2, take a look here: 

 

[ahoeben 1,948]

It never worked with the S5, now that firmware bug has been copied to the UM3 as well. 

[ataraxis 51]

@ahoeben maybe you should comment at the other Thread too, i reported the Bug and will Post it there If i get an answer

[ataraxis 51]

I forked the plugin since the maintainer @ahoeben told me he is not going to change the plugin to be compatible to the new firmware. here you find a compatible one: https://github.com/atar-axis/Cura-ZOffsetPlugin

 

This fork does not use G92 but is adding the offset to every G0/G1 Z value.

 

I opened a PR on the original project: https://github.com/fieldOfView/Cura-ZOffsetPlugin/pull/5

 

Tested on UM3 with latest fw 5.2.?, works.

Edited April 18, 2019 by ataraxis

[ahoeben 1,948]

1 hour ago, ataraxis said:

he is not going to change the plugin to be compatible to the new firmware

 

Thanks. That's not exactly what I said.

 

What I said was that I think this needs to be fixed in the firmware. Ultimaker unilaterally decided to break support for perfectly valid gcode.

 

Your approach, while it works, is a lot more post-processing intensive. Saving gcode files is likely going to take noticably longer, for all printers (also those not affected by the bug introduced with the S5 firmware and now backported to the UM3).

 

I will consider adding your alternative approach only for "Griffin" flavor printers. But I would still much prefer if the actual bug is fixed.

 

 

[ataraxis 51]

That's what I would prefer too, but I don't think this is going to happen any time soon 🙂

 

I know this approach is more expensive, but it does at least work - no matter which firmware is installed,

I can easily wait for some seconds/minutes if the print doesn't fail then.

Btw, the difference is not THAT big (around 0,2 seconds on my current 120 layer print).

 

I suggest to add a dropdown field named "z Offset method" or something like that, where you can decide which ob both methods you want to use, something like:

 

1) `classic G92 (fast but not supported by some UM firmwares)`

2) `global offset adding (slow but robust)`

 

You could then preselect one of both types depending on the gcode flavour.

 

Edited April 18, 2019 by ataraxis

[RoboDLC 1]

Does this plugin work with non-UM printers?

I am using CURA 3.6 currently.  Yesterday I installed the available z-offset add-on from "Marketplace".  I entered 0.1mm Z offset.  My reprap delta printer (Folgertech 2020) homed, moved to the bed and then rose 200mm (or so) and started printing in the middle of the air.  The front panel told me it thought it was a 0.1mm.  It should have said 0.28mm, .1mm higher than my first layer setting.

 

Currently this printer is running an older Marlin version.  It is possible that the g-code was not recognized or perhaps was misinterpreted by the firmware.  I plan on updating to the most recent Marlin and trying it again.

 

Thanks,

DLC

[ahoeben 1,948]

16 hours ago, RoboDLC said:

Does this plugin work with non-UM printers?

 

It should, yes. I can't test it with all printers though. Specifically, I don't have a delta so I never tested the plugin with one.

 

I don't know if there is an issue with using G92 with a delta running Marlin.

 

How old is your Marlin? It could be this issue: https://github.com/MarlinFirmware/Marlin/issues/2106

Edited April 19, 2019 by ahoeben

[ahoeben 1,948]

Here's a version that should work with the UM S5 and UM 3 with newer firmware:

http://files.fieldofview.com/cura/ZOffsetPlugin-v6.0.0-2019-04-19T15_13_09Z.curapackage

 

Download the file and drop it into a running Cura window. Then restart Cura.

Feedback is appreciated.

Edited April 19, 2019 by ahoeben