Cura 3 handles sharp thin features better than Cura 5, why so?

[2go 6]

Hello!

 

I am using Cura 3 at home and Cura 5 at work. This is the same STL, pretty much the same slicing settings.

 

Below is an image from Cura 3.

 

 

And this one is from Cura 5.

 

 

Cura 3 gives perfect and smooth results. Any ideas how to make Cura 5 behave the same? Currently it makes sharp angled thin inside edges all jagged, uneven, and rough.

 

By the way, do these white squares in Cura 5 represent the start of the layer? If so, why is there more than one of these squares in each layer?

 

Thank you.

[64Pacific 2]

I am struggling with the exact same issues and have yet to figure out a way to resolve it - it seems that whenever there is a start (which is what I believe the white squares represent) I get a blob of plastic and holes in my models. Like you I have noticed that older versions printed much nicer than than the current version (5.2). Lately I have been throwing more prints in the trash than anything. Currently attempting a firmware update with the hope that this resolves the issue...

[MariMakes 199]

Hey @2go,

 

Ah, this seems to be a bunch of wedges, the Variable Linewidth Engine in Cura 5.x sometimes struggles with that. 

There are settings that you can change to improve this behavior.

You can read more about them here:  https://support.ultimaker.com/hc/en-us/articles/4792077687068

 

The white squares indeed indicate a layerstart like the layerstart/zseam. 

Looking from your screenshot I think it might also be worth checking your resolution settings. 🤔

Do you have a project file for us? It contains the printer and settings we need for troubleshooting. 
To save a project file go to File -> Save project.

 

 

[2go 6]

Hello @MariMakes,

 

Thank you for your answer. Sure, I've attached a test STL and the project file. Below is the screenshot of the best result I was able to achieve on my own with Cura 5.x, while Cura 3.x handles this inner edge flawlessly.

 

 

Any help would be highly appreciated. I'll go and read the article you've linked now. Thank you.

UM2_test.3mf test.stl

Edited January 3, 2023 by 2go

[GregValiant 1,317]

Since the Arachne Engine was rolled into Cura there are additional settings for walls.  Some settings are specific to UltiMaker printers and others were made defaults in an effort to increase accuracy.  They aren't always what you want.

 

Here is the model.  The points are the problem as "knife" edges always are.

 

This is the model sliced with your settings.

 

The "Outer Wall Inset" at 0.025 is hurting the slice because it makes the "points" 0.05 narrower.  That coupled with your "Line Width" at 0.4 is keeping the nozzle from getting to the end of the points in an "Out and Back" move.  The "Wall Transition Angle" at 10° is also hurting the slice.  With those settings Cura is calculating the move as "Out - Travel - Continue".  That is indicated by the white spots showing where the extrusion starts at the very tip of the point.  Not good.

 

This is with Outer Wall Inset = 0, Line Width = 0.35, and the Wall Transition Angle = 5.0°.  With those settings Cura calculates the move as a sweep out to the point and then a continuation back along the other wall.  There is no longer a "Start-Stop" at the end of the points.

 

This behavior can also be noted if you try to print something like a hair comb.  Each tine of the comb needs to be an "Out and Back" extrusion rather than "Extrude Out Tine 1 - Travel over to Tine 2 - Extrude Back Tine 2" moves which leads to stringing and half the tines get welded together at the tips.

[MariMakes 199]

Hey @2go,

 

What an interesting model! 
That's definetly a lot of wedges. 

Personally I would change these settings to get a better result:

[2go 6]

Thank you both for your help. I was using Cura 3.6.0 for so long now, since it just worked for me, not even aware of new Arachne slicing engine and a bunch of new settings. Will spend this upcoming weekend getting familiar will all the new stuff.

 

@GregValiant I believe I've added 0.025 mm outer wall inset years ago when Cura was insisting on adding tiny bits of infill between two walls whenever I had 0.8 mm thick curved features, and simply forgot about it. I see this is not an issue anymore since variable wall thickness became available. Anyway, I was not able to 100% successfully replicate your result by using the settings you mentioned. If it is not too much to ask, would you be able to share Cura profile file or a saved project?

 

@MariMakes It's not something I actually print, but I drew this cute little bird to illustrate the problem in somewhat exaggerated way 🙂 Your solution is very helpful, I was able to replicate 99% of your result, except for the very clean Z seam, mine looks way messier. Could it be because I use 5.1.0 instead of the newest 5.2.1? If so, I would probably need to update my OS to get 5.2.1 running. If that is not related, if it is not too time consuming, would you also be able to share Cura profile file or a saved project? That would be very helpful. Thank you.

[GregValiant 1,317]

Hi @2go.  A project file is attached.  I didn't spend as much time on this one.

The rollout of 5.0 was kind of bumpy as the Arachne engine was integrated into Cura at the same time that all the dialogs were re-written to work with QT6 controls.  It was ambitious.

5.1 was much better and 5.2.1 continued to evolve and is certainly less buggy.  There is still a slicing bug on Windows systems but moving and/or rotating the model on the Cura build plate usually fools the bug.  You didn't mention which operating system but I've run all Cura versions on an older Windows 10 system with no problem.  If the video subsystem doesn't support OpenGL 4.1 then Cura falls back to "compatibility" mode which is a flat line preview rather than the 3d looking preview.

GV_test.3mf

[2go 6]

@GregValiant, thank you for the project file! I am using macOS Catalina, 5.1.0 is the last version that supports it. Will be upgrading soon to have access to the future Cura versions. Thank you for your help, really appreciated.