Does anyone know why some .stl files have a preview when viewed within finder in OS X versus some that don’t? I was looking at the file details and parameters when comparing two files but didn’t see anything readily obvious.
Well nice that os x has that or did you install an extra viewer which does that? Well i suggest that some are binary stls and some are ascii 
@VolksTrieb this is standard for OSX.
@Tim_Sills Could it be that you never opened the files without the preview?
Ascii stl vs Binary stl would be my guess
Thanks guys for the feedback.
@Jean-Francois_Talbot got it.
I went back and exported the same file I had created as ASCII, and what do you know…it’ll show up in preview when viewing in Finder. I would’ve expected binary to have shown up, but it looks like the other way around. To further test, I took another .stl D/L’d from online that didn’t have a preview, ran it through netfabb and exported as ascii and the preview is there.