Binary STL Previews on Mac?

There is an issue[1] about binary STL files exported from SketchUp showing up as black when using the Mac preview app.

I wanted to ask if someone who uses Mac could help confirm and troubleshoot the issue. It would be nice have SketchUp binary STL files look nicer in the preview.


  1. Binary preview is solid black in macOS (but ASCII is ok) · Issue #163 · SketchUp/sketchup-stl · GitHub
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the binary cube example downloadable from here, shows in quicklook preview the same as an ascii stl…

STLB Cube:

the waves are from the gif, not seen in Finder…


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Thanks to @john_drivenupthewall for identifying the problem. It turned out we were not writing the face normals to the binary stl file.

Made a few corrections - would some kind mac user(s) please make sure this file appears properly (not black) in Mac’s quick look preview?

su-cube-1mm.stl (684 Bytes)

works for me…


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And for me…

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Thanks John. And you too, John.