Improve object repairing from printabrick.org

[gsedej]

Version

1.42-0alpha5

Operating system type + version

Linux (Ubuntu 18.04)

Behavior

The "Lego" bricks obtained from webpage http://printabrick.org/ are problematic to slice. The rendered model (non-sliced) looks OK, but after slicing, models breaks. Sometimes very much.
The below are just two examples. Many bricks (stl files) have many issues printing.

Project File (.3MF) where problem occurs

Upload a Slic3r PE Project File (.3MF) (Plater -> Export plate as 3MF for Slic3r PE 1.41.2 and older, File -> Save / Save Project for Slic3r PE 1.42.0-alpha and newer)
the 3mf upload does not work (using drag an drop)...
The parts are in set https://printabrick.org/sets/8225-1
The number of part is 2994 and 6578
https://printabrick.org/bricks/2994
https://printabrick.org/bricks/6578
The printabrick website sometimes isn't accasable.

Screenshots
correctly rendered wheel

missing axel holders after slicing

should be hole

Tyre - redered correctly

problematic slice - should be hole, but it's filled

[BerndJM]

Just for the records it's the same "problem" in Silc3r 1.41.3

To be honest, I do not think it's fair to blame a slicer when a STL file is totally broken.
Slic3r itself already fixes 888 errors! in the wheel.

I myself have been using Netfabb-Basic for a long time to repair broken STL's with a 99% success rate. But even Netfabb-Basic fails to repair this wheel terrific!

[bubnikv]

@gsedej I wonder whether you shouldn't issue a bug at printabrick.org

[gsedej]

I agree with both comments - the stl files are broken.
Use of Netfabb is suggested, but Netfabb stopped supporing linux. I know there are also some online tools, but either for pay or at least they need legitimate logoin main.

Also I don't know how much can printprick.org do a help. They use LDraw library for models. They have github, but for the webpage. Maybe one could also report models.

I ask slice3r (PE) developers if they plan to improve fixing broken stl-s.

Slicing also depends on orientation. If I rotate object, I can get hole, but still no axel holder. Also much more errors (which can be somehow fixed with "detect thin walls" option)

(the fix with "detect thin walls" and "detect pridging primeters")

Using Cura 3.6, sliceing is done better.

But also broken, when rotating to preffered printing position.

[BerndJM]

but Netfabb stopped supporing linux

Netfabb-Basic for Linux is still available for download up to version 7.4
https://github.com/3DprintFIT/netfabb-basic-download/releases

[gsedej]

Thanks for suggestion. I did try fixing with netfabb, but even it didn't solve.
(it did help me with other parts, and I didn't have to give my phone number like online solutions)

So I ask the developers if they can improve the repair algorithm.
If they don't plan to investigate broken models from printabrick.org, the bug can be closed (as wontfix or not-a-bug, etc)

[bubnikv]

One of the models has randomly flipped triangles:

[MisterPrintf]

Don't even bother. Printabrick is ethically wrong, and, in some cases, copyright violation. Give LEGO their money!

[gsedej]

@MisterPrintf You mean buying single/few bricks from 20 years ago? It's not like I am printing full brick set and potentially selling it. IIRC LEGO lost it's patent since there are many (chinese) companies selling full sets. Why would I hurt LEGO by being able to print out missing/broken/eaten pieces for my old collections?

On the topic: is there any Slic3r or Slic3r-PE developer that can comment on improving printaprick.org models stl slicing? Should I leave this issue opened?

[MisterPrintf]

Honestly, Tinkercad's algorithm fails on most printabrick models, so I woudn't even touch it.

@gsedej That was my bad there. Lego has a near-identical piece still in production and I didn't bother to look closely. Still, printabrick's models are taken directly from ldraw which does not permit high-poly shapes so you are better off designing your own models.

[bubnikv]

printabrick dead, the models are no more available.
Closing.