Exporting OBJ mesh in blender I am trying to export a simple shape: torus, sphere. the exported mesh is in OBJ format. Blender displays an error "location is unknown or something related to volume. If I increase the scale to 100 ( setting of OBJ export) still the error displayed. Do you have any idea why I cannot get the OBJ mesh?

Traceback (most recent call last):
    File "/Volumes/Blender/Blender.app/Contents/Resources/2.80/scripts/addons/io_scene_obj/__init__.py", line 311, in execute
        return export_obj.save(context, **keywords)
    File "/Volumes/Blender/Blender.app/Contents/Resources/2.80/scripts/addons/io_scene_obj/export_obj.py", line 791, in save
        EXPORT_PATH_MODE=path_mode,
    File "/Volumes/Blender/Blender.app/Contents/Resources/2.80/scripts/addons/io_scene_obj/export_obj.py", line 733, in _write
        progress,
    File "/Volumes/Blender/Blender.app/Contents/Resources/2.80/scripts/addons/io_scene_obj/export_obj.py", line 389, in write_file
        bpy.data.meshes.remove(me)
    RuntimeError: Error: Mesh 'sphere' is outside of main database and can not be removed from it


The link to the files:

The STL mesh: https://gofile.io/?c=iycaiS

Blender file:https://gofile.io/?c=yLi0Pp
This issue appears when you're trying to export an object that contains no geometry, because of a single erroneous line in export_obj.py. This bug has already been reported and fixed in D5479 by Philipp Oeser. The fixed version of the exporter will be available in Blender 2.81.

In your case the object 'sphere' contains no geometry, which triggers this error. As a workaround until 2.81 is released you can either just select objects that contain geometry and enable Selection Only in the exporter or you could simply delete the problematic object. Alternatively you could also change the one line of code in the obj exporter yourself.