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prusa3d / PrusaSlicer

G-code generator for 3D printers (RepRap, Makerbot, Ultimaker etc.)
https://www.prusa3d.com/prusaslicer/
GNU Affero General Public License v3.0
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Slicing errors in "detect thin walls" mode #2583

Open mkoistinen opened 5 years ago

mkoistinen commented 5 years ago

(Possibly related to #227 and #149, but perhaps this will provide additional clues to the core of the issue?)

Version

PrusaSlicer 2.0.0 - 201905201652

Operating system type + version

MacOS 10.12.6

3D printer brand / version + firmware version (if known)

Original Prusa i3 MK3S, latest firmware

Behavior

I designed a part in Fusion 360. It consists of the primary body and additional bodies which are custom supports. These are pretty thin (0.405 mm) so I have to enable "Detect thin walls" in the Print settings. When I merge the bodies together into a single part before exporting to STL, it slices fine in PrusaSlicer and prints beautifully.

If I export the separate bodies as a single STL from F360, it loads perfectly fine into PrusaSlicer and displays perfectly in the Platter view (see 1st screengrab). However, when I slice it, some tiny (but important) fragments of just 3 of 20 of the custom support bodies are just missing, even though their construction is identical to the remaining 17. (see 2nd and 3rd screengrabs).

I have also tried the "Repair STL file..." in PrusaSlicer. It claims to have fixed the STL (saved as an Obj), but it makes zero difference. Obviously, the workaround is to export everything as a single body from Fusion 360, but it is not ideal.

Interestingly, slicing only the custom support bodies with the same settings does not exhibit any slicing errors.

I was expecting no difference between exporting as a single body, vs. as separate bodies before slicing.

Inexplicable bits are missing from the sliced part if the STL was exported from multiple bodies from F360.

image Model in the Platter view

image Sliced model in the Slice view

image Layers above the affected area removed to better show the issue

image Slicing only the custom supports with the same settings does not exhibit the same issue

Is this a new feature request? No.

Project File (.3MF) where problem occurs

The 3MF file and the single body STL file can be found here: https://www.prusaprinters.org/prints/3873-gopro-hero-7-cozy.

The multi-body STL file is here for your inspection: Mount w:Separate Supports.stl.zip

Jebtrix commented 5 years ago

PrusaSlicer 2.0.0 - 201905201652 Win7 Pro 64bit

The .3MF file slices just fine for me. MacOS version related in some way maybe?

mkoistinen commented 5 years ago

The plot thickens...