1st layer over a rectangular void slicing the wrong direction and not using the scaffolding

[tturkstra]

Version 2.3.0+

Version of PrusaSlicer used goes here Use About->About PrusaSlicer for release versions

For -dev versions, use git describe --tag or get the hash value for the version you downloaded or git rev-parse HEAD

Operating system type + version Mac OS Big Sur 11.2.1

What OS are you using, and state any version #s 11.2.1 In case of 3D rendering issues, please attach the content of menu Help -> System Info dialog

3D printer brand / version + firmware version (if known) Prusa Prusa i3 MK3S+, but problem is slicer and can be seen before the G-code is even sent to it.

What 3D printer brand / version are you printing on, is it a stock model or did you modify the printer, what firmware is running on your printer, version of the firmware #s

* Describe the problem

Behavior Slicing a fairly simple object with a large box with a box "removed" leaving a long, narrow, 20x3 cm "table top". Selected the option for "Support on build plate only". Supports are built perfectly, but the 1st layer of the "table top" prints in the wrong (longitudinal) direction, basically not using the Supports. Thus that layer basically falls away in strands. The next layer is OK, but it would be much better to have the 1st "table top" layer go across the rectangle across it's shorter dimension and use the supports. I include the stl that was being sliced and a screen-grab showing the offending layer. NSX Battery bar (3).stl.zip

• Steps needed to reproduce the problem STANDARD DEFAULT SETTINGS + SUPPORTS ON BUILD PLATE.
  • If this is a command-line slicing issue, include the options used
• Expected Results 1st layer should go across short axis of the rectangular void from the object to the supports
• Actual Results 1st layer goes across long axis of the rectangular void
  • Screenshots from PrusaSlicer preview are preferred

Is this a new feature request? No

Project File (.3MF) where problem occurs

Upload a PrusaSlicer Project File (.3MF) (Plater -> Export plate as 3MF for Slic3r PE 1.41.2 and older, File -> Save / Save Project for PrusaSlicer, Slic3r PE 1.42.0-alpha and newer) Images (PNG, GIF, JPEG), PDFs or text files could be drag & dropped to the issue directly, while all other files need to be zipped first (.zip, .gz)

[bubnikv]

Actually the bridges should not be supported at all if "don't support bridges" is enabled at the support parameter page.