I think the visible invisible objects may have to do with surfaces of the object. I still trying to figure out wrongly oriented normal, double surfaces and two sided exports, but most decent models (even with some formal errors) will vanish nicely in SH3D with an invisible texture (probably very similar to yours, only 64×64 - as, apparently, some Wavefront (.obj) implementations may run into trouble if the pixel size is not a multiplier of 2 - but now I am really out of my depth).

But just for the record - the picture of the sofabed was intended show the ghost fold-out (20% opacity) - easier to see whether there is enough space when planning. If I apply an invisible texture - my ghost bed also vanishes (at least from the 3D view).

ok