Nice feature, thanks a lot.
It's very nice to be able to export/use a model without the extra floor. However... it's still a bit buggy.
(1) It doesn't work correctly with the sh3d.jnlp version. First time I tried it asked for a browser location, the second time it dodn't work at all.
(2) The installed version of SH3D works correctly. However, it seems you changed something in the coding of the Export to OBJ format routine. The quality of the rendering of the exported object is much lower than the quality of the original. And the applied texture isn't correct on at least one side of the combined object. It doesn't matter whether you use Tools --> Copy or 3D View --> Export , both give exactly the same result.
Hans