Sadly I can't reproduce this on Unity 2021.2.0f1 ... OBJ export still seems to work OK for me. I was able to paint new ivy and export + import to OBJ successfully.

• Do any error messages appear in console when you try to export? You should see a message like ObjExport: saved .OBJ to /Assets/Samples/Ivy[20](-5.4, 0.6, 4.9).obj
• Does this still happen for you if you try to export the demo ivy meshes from the ExampleHederaScene ? Or is it only broken for new ivy meshes that you've painted yourself?

There is no error and the file is created, message is showing in console like you mention it, but when i put it to the scene by hand or when it asks to replace current instance with obj file the object is just an empty gameobject.

Can you upload some kind of project folder or small minimal repro project so I can download and investigate? Sorry I have no idea what's wrong.

Ok, I will do it this evening.

Ok so I created empty project and there is the same thing. I uploaded it to box.com, here is the link:
https://app.box.com/s/a92uym4wdliycdtivmtjy2t2ben7umdk

Thanks. I've downloaded it but I'm currently busy with other work, hopefully I'll get around to this in a week or two.

I do have one suspicion though: if your OS is set to a locale or region that uses comma separators for decimal numbers, there might be a problem with serialization / numbers. In English-speaking countries / US region (which is what I dev on), it would use periods for decimal separators. When I have time, I'll investigate this.

OK, thanks. I will check that setting.