Assert error in vector (in Debug solution) using Arachne engine

[jmd73]

Description of the bug

Assert message:

If slicing using release build, it slices fine, so maybe the fault is not anything critical at all. In that case you are free to close this issue.

The fault happens at generating perimeters (at about 20%)

Exception happen in file at line 88 ( _STL_VERIFY(_Mycont->_Myfirst < _Ptr, "can't decrement vector iterator before begin");"

Call stack (click to expand):

PrusaSlicer.dll!std::_Vector_const_iterator>>::operator--() Line 88 PrusaSlicer.dll!std::_Vector_iterator>>::operator--(int __formal) Line 294 PrusaSlicer.dll!Slic3r::Arachne::removeSmallAreas(std::vector> & thiss, const double min_area_size, const bool remove_holes) Line 351 PrusaSlicer.dll!Slic3r::Arachne::WallToolPaths::generate() Line 485 PrusaSlicer.dll!Slic3r::Arachne::WallToolPaths::getToolPaths() Line 681 PrusaSlicer.dll!Slic3r::PerimeterGenerator::process_arachne() Line 578 PrusaSlicer.dll!Slic3r::LayerRegion::make_perimeters(const Slic3r::SurfaceCollection & slices, Slic3r::SurfaceCollection * fill_surfaces) Line 105 PrusaSlicer.dll!Slic3r::Layer::make_perimeters() Line 192 PrusaSlicer.dll!Slic3r::PrintObject::make_perimeters::__l2::(const tbb::detail::d1::blocked_range & range) Line 215

Attached is the project that causes the fault when slicing.

All that is needed to replicate, is to load the STL (got it from here: Thingiverse link) and rotate it 90 degrees to get it facing forward.
If the object is not rotated, the error does not occur.

If I left something out, please let me know.

Project file & How to reproduce

3mf project file; frog_toothbrush_holder_.zip

Original STL file: frog_toothbrush_holder.zip

Checklist of files included above

• Project file
• Screenshot

Version of PrusaSlicer

version_2.5.0-alpha3-14-g394494b3a (64bit debug build)

Operating system

Windows 11 64bit (build 22000)

Printer model

MK2.5S & MK3S+MMU2S

[hejllukas]

Thank you for reporting this issue. It was fixed with f60b88b in master_250, and it will be part of the next beta.