![[not solved, but worked around] Tinkercad not exporting holes? They don't even show up in the preview. Some of my previously working designs are also doing this.](https://sh.itjust.works/pictrs/image/081bb751-15e9-4ac4-b382-7b783f3a99df.png){kind=link}
I made this test block to test the fit on some holes (my printer isn’t calibrated), when I noticed the problem. The cone on the side was a sanity check for this problem.
I tried googling but couldn’t come up with this same problem.
Edit: I did just figure out a way, I made them a union group, which applied the cuts immediately, and they stayed when exported. I’ve never had to do that before. Though admittedly that’s probably the right way, I normally use fusion360. Something is definitely weird though. It should just work without doing that. And in fact it did a few days ago on a different project file.
Maybe give MatterControl a try.
It is like TinkerCAD in that you drag shapes around, but has way more features and runs locally. And you can easily load in STL files to cut and paste with.