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Can PrusaSlicer Fix a Bad STL?  

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Razor
(@razor)
Estimable Member
Can PrusaSlicer Fix a Bad STL?

So I found this cool "brick company" light switch cover to print for my daughter; https://www.thingiverse.com/thing:2551909 . When I sliced it in PrusaSlicer at .20mm layer height, I noticed some odd lines along the long horizontal edges. I went against my better judgement and printed it anyways. Unfortunately as you can see from the attached photo, the long edges look like hot garbage. It's even worse in person.

I went back in to the slicer and set the layer height to .25 and while not perfect, it looks noticeably better. I'm guessing whoever make the file did not create a flat plane. It's doesn't make sense why someone would do that, but then again it was on Thingiverse... 🙄

Is there some type of magic tool in PrusaSlicer I can use to fix it? Even after changing the layer height there are still small imperfections that bug me. I'm a complete idiot when it comes to Fusion360 or else I would just redraw it myself.

Best Answer by jsw:

Yes, I added two mostly-rectangular areas to fill out the irregular surfaces using FreeCAD.  I filleted the edges to better seamlessly blend in with the surface.

You can try it with no supports if you want.  My hunch is that it would sag significantly, but it will be 'greasy side down' and not show.

If I were doing this one, I would use break-away supports on the build plate with a liberal contact Z distance.  Again, greasy side down and the blemishes from support removal will not show on the installed product.

Mini+MK3S+XL 5 Tool

Posted : 01/11/2022 3:51 am
jsw
 jsw
(@jsw)
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RE:

If you will zip up the .stl file (yes, I prefer .stl files rather than .3mf for things like this) and attach it to a reply, I would be happy to inspect it and see what I can do.

From the visual, it looks like there are some irregular surfaces on the bevels.

Since the design looks rather simple, I might be tempted to simply re-draft it rather than fix a wonky .stl, but I would be willing to see what I can do with the .stl file.

To answer your original question, however, yes, PS has a 'repair stl' function, but I've found that it really does what you want maybe 5% or so of the time.  The PC version has a better fix function using an external program, but I have yet to see any true effective one-step .stl file fixer.

I've had reasonable luck fixing corrupt .stl files by importing the file into FreeCAD, then creating shape from mesh, refining shape, then converting to solid and re-exporting.  This is with the Part Workbench.

Posted : 01/11/2022 4:58 am
Razor liked
Razor
(@razor)
Estimable Member
Topic starter answered:
RE: Can PrusaSlicer Fix a Bad STL?

 

Posted by: @jsw

If you will zip up the .stl file (yes, I prefer .stl files rather than .3mf for things like this) and attach it to a reply, I would be happy to inspect it and see what I can do.

From the visual, it looks like there are some irregular surfaces on the bevels.

Since the design looks rather simple, I might be tempted to simply re-draft it rather than fix a wonky .stl, but I would be willing to see what I can do with the .stl file.

To answer your original question, however, yes, PS has a 'repair stl' function, but I've found that it really does what you want maybe 5% or so of the time.  The PC version has a better fix function using an external program, but I have yet to see any true effective one-step .stl file fixer.

I've had reasonable luck fixing corrupt .stl files by importing the file into FreeCAD, then creating shape from mesh, refining shape, then converting to solid and re-exporting.  This is with the Part Workbench.

Makes sense wanting the STL. Not sure how certain companies react to their names being out there, so I renamed it to a "similar" competitor. 😉

Thanks in advance!

Mini+MK3S+XL 5 Tool

Posted : 01/11/2022 12:57 pm
jsw
 jsw
(@jsw)
Famed Member
RE: Can PrusaSlicer Fix a Bad STL?

Ok, I took a look at it and tried one iteration of the steps which will fix many wonky .stl files and it sure looks to me like those irregularities are in the mesh.

I have some running around to do this morning, including a dentist appointment, but if you can hold on until this evening I'm very confident I can remove most of those boo-boos and re-upload it.

Posted : 01/11/2022 1:48 pm
Razor liked
jsw
 jsw
(@jsw)
Famed Member
RE: Can PrusaSlicer Fix a Bad STL?

This one appeared to be almost too easy.  I hope this is ok.

 

Posted : 01/11/2022 2:44 pm
Razor liked
Razor
(@razor)
Estimable Member
Topic starter answered:
RE: Can PrusaSlicer Fix a Bad STL?

Thanks, I see you added two rectangular sections. I'm assuming this was done in CAD?

Bonus question, the last time I printed I went with full supports underneath it. I'm thinking that can be reduced considerably. Do you think I could get away with only placing supports around the switch hole in the center? Or is that asking too much from the bridges?

Posted by: @jsw

This one appeared to be almost too easy.  I hope this is ok.

 

 

Mini+MK3S+XL 5 Tool

Posted : 01/11/2022 4:33 pm
jsw
 jsw
(@jsw)
Famed Member
RE: Can PrusaSlicer Fix a Bad STL?

Yes, I added two mostly-rectangular areas to fill out the irregular surfaces using FreeCAD.  I filleted the edges to better seamlessly blend in with the surface.

You can try it with no supports if you want.  My hunch is that it would sag significantly, but it will be 'greasy side down' and not show.

If I were doing this one, I would use break-away supports on the build plate with a liberal contact Z distance.  Again, greasy side down and the blemishes from support removal will not show on the installed product.

Posted : 01/11/2022 6:09 pm
Razor liked
Razor
(@razor)
Estimable Member
Topic starter answered:
RE: Can PrusaSlicer Fix a Bad STL?

Well, it took a little while (two kids that play on two hockey teams each, plus two that I play on) I finally had the time to learn Fusion just enough to create my own version that is a.) flat and b.) the bricks actually stay on the cover. 😁

Here's a link to it; https://www.printables.com/model/802875-lego-compatible-light-switch-cover. It took forever to learn, but the journey was well worth it.

Mini+MK3S+XL 5 Tool

Posted : 12/03/2024 3:21 pm
ssmith and Zappes liked
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