Hollow parts?

This can certainly be done with Autocad3D so im sure openScad can do it too, you can also have the LID as a seperate part and simply Acetone glue it in place for a perminant fit

Cheers, may be I'm just overthinking it. I'll just give it a go and see how it turns out. If there are issues I can always go for a lid approach or possibly a very small hole in the bottom.

I think you could draw the object solid then in the slicer set the infill to 0%. It will print hollow. Though the wall thickness could be less than you would like?

Yes, that could work too, I can configure it with a thick wall size and possibly use the rectilinear fill which leaves lots of space for adding weights but would keep the strength.

IMHO i would not leave anything upto the slicer. There are two ways about going into print for an object.

1. For a hollow object, just split it in two and then shell both the halves. Then print them as separate objects. Make sure you add some notches to align the printed halves and then use super glue.

2. For hollow grill like objects or the like, export an STL and then add supports in mesh mixer. It allows you to do supports, and all that stuff.

Hit print, fingers crossed and tongue at the right angle...

Bam!

I agree with IP, it is not necessary to leave it to the slicer, see this example of something I did for my Kitchen

Full BOX and lid

Hope this will help