Can you explain the square in this picture? Exporting object

Im trying to export a .obj and get this strange black grid being exported alongside my desired object. Can anyone tell me what that is and why it is there?

BEFORE: Object to be exported

AFTER: Object exported as .obj or .3ds. What is this black grid?

No idea from just the images.
Can you please post the 3DM file?

Figured it out.

I had a hidden layer containing a picture that I was using for reference. I just deleted that hidden layer and exported and now its fine.