OK So I designed this as a miniature house for video and film making. The insides of the house have walls and holes in the bottom, this is because I have simple LED wiring in mine so that I can make it look like the inside is being lit.
The model seems to have some weird conversion error. The previews are a little weird. Doesn't seem to matter though because it printed fine.
All my models can be used commercially, I dont care how much money you make off 3d printing them.