Layers have the wrong color or are entirely missing when slicing multimaterial
 
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Layers have the wrong color or are entirely missing when slicing multimaterial  

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Oak
 Oak
(@oak)
Active Member
Layers have the wrong color or are entirely missing when slicing multimaterial

I'm slicing a complex model that has "multimaterial painting" data. For the most part the slicing seems good, but it has two frequent critical issues:

  1. There are the occasional horizontal segments in which the color is wrong.
  2. Sometimes a few layers are altogether missing from some islands. The slicer adds top and bottom shells before and after. Other islands will continue growing layers as usual.

Needless to say, the result is unprintable - the first problem would generate considerable visual glitches, and the second results in islands in the air. I'd appreciate any advice on what I can do to bypass these issues. While it might be a slicer bug, the model is not problem free - it has 100,000 open edges that I haven't found how to fix while maintaining the color information. I've attached the 3mf file at the bottom of this post.

Here's how the model looks before slicing:

And after slicing, with highlights around the vertical artifacts and the missing layers. Notice how the bad layers are surrounded by many good ones.

 

Here are some close ups of a problematic layer. The first image is right beneath it, the second is the bad layer, and the third is right after it. It really shows how it's one really confused layer in between two good ones.

 

The file in question:

Tallneck 5 colors

Posted : 21/08/2023 6:21 am
Diem
 Diem
(@diem)
Illustrious Member

Please upload files here - Many of us don't want our use to be tracked by certain other sites.

But the answer is clear - fix the broken source file; no slicer can guess what is missing or misplaced or inside out when given a corrupt file.

You don't say which design software you are using but it's clear that it is there you must look for the answer - there is an option in slicer to submit a file to online tools to attempt repair but that software too has to try and second guess the design.

Tell us which CAD you are using, there may be someone on here who can help, but you would be better to go to a user group for that CAD software where the relevant expertise is likely to be concentrated.

Cheerio,

Posted : 21/08/2023 7:40 am
Oak
 Oak
(@oak)
Active Member
Topic starter answered:
RE:

Thank you for your response!

Posted by: @diem

Please upload files here - Many of us don't want our use to be tracked by certain other sites.

I used this forum's own "add media" feature to upload a zip, is there another way to upload a file here?

But the answer is clear - fix the broken source file; no slicer can guess what is missing or misplaced or inside out when given a corrupt file.

You don't say which design software you are using but it's clear that it is there you must look for the answer - there is an option in slicer to submit a file to online tools to attempt repair but that software too has to try and second guess the design.

Tell us which CAD you are using, there may be someone on here who can help, but you would be better to go to a user group for that CAD software where the relevant expertise is likely to be concentrated.

Cheerio,

Unfortunately, this isn't my model - it's an IGS file made in CATIA V5 by "Gloomeskk" (sketchfab link), I just loaded it up in Fusion 360, fixed some (many) surfaces which were inside-out, then manually added slic3r color information to the 3mf.

As for fixing services - I only made this post after I couldn't find one that worked correctly:

  • I tried Prusaslicer's own "fix through the netfabb" but unfortunately it strips all multimaterial information out.
  • I tried Microsoft's fixing service through "3d builder" but it apparently made up dozens of fake colors and applied them all over. Still not sure why, maybe it's manually fixable.
  • I tried Meshmixer's "analysis" and "auto fix" feature but it seems to outright remove offending parts from the model. Maybe I just don't know how to use it correctly, it's a fairly complex one to use.
  • I tried fixing mesh warnings through Fusion 360's mesh tools, but they also seem to strip the color information out.

You are right that the best option is to fix the source, but my past experience suggests that slicers can in many cases power through the warnings - like Prusaslicer did succeed in doing in many of the other layers here - which is why I'm hoping someone has some tips on how to help Prusaslicer here.

But meanwhile it's a good idea to approach CATIA users and ask them about that, I'll give it a shot, thanks!

This post was modified 8 months ago by Oak
Posted : 21/08/2023 3:54 pm
JoanTabb
(@joantabb)
Veteran Member Moderator
RE: Layers have the wrong color or are entirely missing when slicing multimaterial

Tallneck 5 colors  Original file.

Your model, as supplied, is approximately 525mm tall, with nearly 70K errors.  
it's going to be a little difficult to print on the Prusa family of printers at that size.  how do you propose to print the model? 
slicing the model into sections, loses the multi material painting. 
re sizing the model retains the multi material information but does nothing to the errors

You are correct that using fix with the netfabb, strips out the painted on colour scheme.  but it does seem to fix the errors

as supplied, the purge tower, conflicts with the model for space on the build plate. 
If you re size the model, to fit within the normal build volume, the purge tower will not be an issue. 

below is a .3mf file with the printer Z height set to 550mm so that the model will not raise errors for exceeding the build plate size and it has been fixed with the netfabb. but you are going to have to complete the multi material painting again. 
Tallneck repaired

Note this file does not have any supports in it. you will need to add supports, in order to print this file
I suggest organic supports. 
regards Joan

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK

Posted : 21/08/2023 6:48 pm
Oak
 Oak
(@oak)
Active Member
Topic starter answered:
RE: Layers have the wrong color or are entirely missing when slicing multimaterial

 

Posted by: @joantabb

Tallneck 5 colors  Original file.

Your model, as supplied, is approximately 525mm tall, with nearly 70K errors.  
it's going to be a little difficult to print on the Prusa family of printers at that size.  how do you propose to print the model? 

Thank you for the response! Yes, the model I attached is before more slicer work - it obviously needs to be further prepared for printing with resizing, adding supports, moving the priming tower, and also some rotation for better print alignment. I'm sorry if I wasn't clear on that... the fact that it's a 3mf file is because that's how I produced it, not because it's a saved PrusaSlicer project (which it isn't).

The layer errors I mentioned in my first post are there whether these operations are applied or not, so I just showed them before these operations to make things easier to see.

Posted : 21/08/2023 7:22 pm
Oak
 Oak
(@oak)
Active Member
Topic starter answered:
RE: Layers have the wrong color or are entirely missing when slicing multimaterial

Update: I was able to resolve the problem! If anyone is running into a similar issue: Microsoft repair option in 3d Builder indeed preserves the material extension information, and this can be used to derive slic3r mmpainting data, so I was able to maintain the color data during the fix.

It does add hundreds of additional colors, but I'm guessing these are associated with the new triangles only. By not assigning any `slic3rpe:mmu_segmentation` data on them, PrusaSlicer just ignores them completely - which is what I want here.

Posted : 22/08/2023 8:46 am
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