Cura Slicing Problem – Issues Slicing Rounded Surface…

[oo7_golden_1 0]

Hello Ultimaker Cura Community,

 

I want to start out by saying that I really really really like to use Cura as my slicer. The features it provides makes slicing as smooth and streamlined as possible. Recently however I have been making custom Christmas gifts for friends and family members and have seemed to hit a snag that Cura is having a lot of trouble with.

 

At first, I thought it was the model itself but after extensive troubleshooting it would seem that the fault lies with Cura not slicing the model properly.

 

ANY help would be greatly appreciated.

 

Here is the problem…

 

I have multiple models that contain a smooth rounded face. This curvature has a Radius equal to about 80% if I am not mistaken).

 

When I import the model into Cura it appears as it should. Smooth, round, clean and beautiful. Once I slice the model however Cura for some reason converts that smooth rounded face into a polygonal shape. Which wouldn’t be horrible if it did it for the whole model. But for some reason it seems to slice the bottom of the model correctly and then not so correctly else ware.

 

I have done my best to solve this problem on my own but have concluded that it is a problem with the Cura Slicer.

Here is a list of some of the troubleshooting I have performed:

 

1.       Printed multiple models (different models with the same radius/curve).

2.       Updated Cura to the latest version.

3.       Verified that these abnormalities were showing after slicing the model in Cura ruling out hardware issues with the printer (CR10S).

4.       Imported the models into three different 3D software programs to verify that the models where not the issue.

5.       Verified that the model(s) imported into Cura correctly. Cura shows and displays the model correctly until the model is Sliced.

6.       Verified the curved round edge of model turns into a polygonal shaped after slicing. This happens on any smooth area of the model. Rough areas seem to slice correctly.

7.       Tried adjusting the resolution under the advanced/experimental settings in Cura.

8.       A few other users within the Lithophanemaker Community on Facebook had the exact same issue, which rules out a problem with my specific Cura installation.

9.       Downloaded, installed and configured the PrusaSlicer to work with my (CR10S) which was able to Slice the model without issue.

 

Any suggestions as to how I can resolve this problem? I have spent a lot of time and love dialing in my Cura settings for my printer and would rather not have to configure another slicer program.

 

Any and all help is appreciated.

 

Brian B.

[burtoogle 516]

Is it possible to provide the project file? If so, please save it (File -> Save) and attach the .3mf file to this thread. Thanks.

[oo7_golden_1 0]

I have been troubleshooting all day with no success. I am still having the problem in Cura. I generated a few test files to troubleshoot with which I will upload along with the .3mf files.

 

If you look at these test files Cura does a pretty decent job slicing the bottom of the frame correctly (round) but on the top of the frame it still slices it as a sort of polygon shape.

 

I hope it helps.

 

Thank you for taking the time to help. I appreciate it.

 

Brian B.

 

P.S. I can get these .STLs to slice properly with the PrusaSlicer but the PrusaSlicer doesn’t offer some of the settings/features that Cura offers and that I am wanting to use for these prints, such as Combing.

 

Again, thank you for your help.

cura-tests-01-04-curved-to-poly-bug-3mf-files.zip cura-tests-01-04-curved-to-poly-bug-stl-files.zip

[burtoogle 516]

Sorry, those .3mf files are not project files as they only contain the model and no settings. Please just save a single project using (File -> Save) and attach just that .3mf file. Thanks.

[oo7_golden_1 0]

Hi again Burtoogle,

 

I suppose I misunderstood your instructions.

 

I opened the .stl file with Cura, verified that the profile I wanted to use to slice the model was selected, sliced the model, selected “Save to File”, Save as type: 3MF file (*.3mf), clicked “Save”. Then I zipped them up and uploaded them here.

 

I did not File > Save as requested. My apologies.

 

I have uploaded the single .3mf project file.

 

Thank you again for your assistance.

 

Brian B.

 

P.S. I have tried many different settings to get the models to slice correctly. Did you try to slice any of the .stl files with your own configuration to see if it converted it to a polygon? A few other people online are having the same problem that I am.

 

In any case, thank you for taking the time to help. I look forward to your reply.

CCR10S_test002-blank-background.8min-thickness.3mf

[burtoogle 516]

Thanks for the project file. I think what is going wrong is that there are Cura bugs that cause the outlines to go all "low poly" when the model is very high resolution and the max deviation settings is small. I know that sounds paradoxical but it's true. If you increase the values of max resolution and max deviation the outline should become smoother but then the detail in the model can get lost. Alternatively, you can install one of my Cura builds that has the bugs fixed. You can get a build from https://www.dropbox.com/sh/s43vqzmi4d2bqe2/AAADdYdSu9iwcKa0Knqgurm4a?dl=0 Please read the README.md file there.

 

Here's what I see when I slice your project using exactly the same settings and my Cura...

 

 

[oo7_golden_1 0]

Thank you Burtoogle,

 

The model is of a high resolution. I assumed it was a bug of some kind.

 

I did play with the resolution settings in Cura a bit and had the same concern that you mentioned in that the details of the model might get lost (which I didn’t really want to happen).

 

The image that you uploaded is what I am seeking to accomplish when I slice the model in Cura. I went to that link (thank you for providing it), read the README.md file. I saw the “20190823 - Upstream changes + bug fixes (polygon simplification, duplicated prime tower brim)” Part. That might be what you were referring to in your latest post.

 

To be brutally honest I am not sure what I am looking at or looking for in that link.

 

Are these official development releases from Cura? Like betas for testing? Are they plugins? Or are they personal Cura releases with your own additions/tweaks? Could I access these through Cura’s official github page? How would I choose the proper thing to install? Would I have to uninstall the Cura 4.4 version that I am currently using? Would it affect future official updates?

 

You seem to be a very active and helpful member on this site and I appreciate all that you have done to help me and I am seeking a quick resolution so that I can resume printing some holiday gifts for my friends and family but I am always a very cautious fellow when it comes to downloading unknown software and programs from an unknown Dropbox or Google Drive recommended by a stranger on a forum to which I am a new member.

 

There are too many shady people out there these days. Not that you are one by any means, your activity on this forum shows that pretty clearly.

 

In any case I suppose I am just looking for a quick safe fix to get back to printing.

 

How do I determine what “Cura build” to try? Are they installed like any other program? Could I get your working version of Cura from that link? Will it work for my 64-bit Windows 10 PC?

 

If possible is there an official Cura source I can access that Dropbox from?

 

Could you point me in the right direction?

 

Thanks again for all your help.

 

Sincerely,

 

Brian B.

[burtoogle 516]

Hello Brian, those releases are built from UM's development source (the master branches) with a bunch of bug fixes and, IMHO, improvements that I have worked on. So they are basically what is going to be in the next UM cura release with the additions/fixes that I have added. Nearly all of the changes I have made are offered to UM for incorporation in their releases but, for various reasons, they don't accept quite a lot of the stuff I have done so my releases have diverged somewhat from the UM releases.

Anyway, my releases can be installed alongside the UM releases without conflict. You only ever need to install the most recent release as it contains all the changes in the previous releases. Whether they are trustworthy or not, it's not for me to say, but I haven't yet received any complaints that running my Cura has sent the contents of the user's PC to China. YMMV.

[oo7_golden_1 0]

You are on the ball my friend.

 

Is it just the most recent .exe file? In this case “Cura-mb-master-win64-20191209.exe”? Will it just install as any other program would? Anything I should be aware of?

[burtoogle 516]

11 minutes ago, oo7_golden_1 said:

Is it just the most recent .exe file? In this case “Cura-mb-master-win64-20191209.exe”?

 

Correct.

 

12 minutes ago, oo7_golden_1 said:

Will it just install as any other program would? Anything I should be aware of?

 

It is packaged just like the UM releases and so should install just like those.

 

Other than scanning the README.md file (you already have), I don't think there is anything else you need to know.

Good luck!

[oo7_golden_1 0]

Sweet. Ill give it a try right now.

[ArcticEddie 0]

I'm having the same problem with 4.4.1 and found no solution. It's creating some very messy, and unusable, thin wall cylinders. I don't have the problem with 4.0.0 but that version on Win7 periodically does not show the build plate. At what version does this polygon problem start? I'm using an Ender-5 and would like to use 4.2.1 or newer, but without the polygon problem.

[burtoogle 516]

Hello @ArcticEddie, as mentioned above, you could try one of my builds which are available at https://www.dropbox.com/sh/s43vqzmi4d2bqe2/AAADdYdSu9iwcKa0Knqgurm4a?dl=0. Please read the README.md file there for more info.

[ArcticEddie 0]

I've managed to solve most of the problem by going back to DesignSparkMechanical, DSM, and setting the STL facet options to the highest resolution. I'm still having a problem with the infill of a stepped cylinder. When it gets to the upper thinner portion, it prints two very short lines on one side then crosses over, leaving strings, and does the same thing on the opposite side. Both the cylinder and shell wall thickness are 1.2mm. I have not tried enough combinations of wall and infill to get a solution.

 

[gr5 2,267]

Be careful setting facet too high.  Cura will slice all the triangles in the STL with a plane which gives you lots of lines segments.  If there are too many line segments the gcodes may be as little as 0.1mm long or 0.01mm long and trying to print so many tiny movements will actually print very slow.  Maybe even as slow as 1mm/sec.

 

[ArcticEddie 0]

One of my problems is solved with the resolution change in DSM. I can back off on the resolution to where it starts again. I have also stumbled on the solution to my second problem after searching other topics. My only remaining question is what is the last version before the polygon/facet problem started?

 

[rcoti 0]

If you want to get a round surface as your 3D model is, you need to change your resolution and maximum deviation that you can find in your correction settings, just read the setting guide about this parameters and you'll understand why after slicing it make that kind of shapes.