Yes, sorry if my terminology there was sloppy, by “realtime usage” I indeed referred to IPR inside sketchup. So what I am saying is that you should expect a fully interactive experience inside of sketchup, with the option of sending out to bella GUI (or CLI) for final production render — if that is desired (whether on the local machine, or elsewhere).
That said, we have talked about a realtime engine like you mention since early on, but I think it will be quite awhile before we could justify playing with that, as we have yet much to do in core bella. On the other hand, we do have a colleague who did an excellent (both in result, and in being very nice code) realtime engine for a project at our previous company, who we’d love to get on board if bella sees enough success to make it possible, so who knows.
Regarding the export script for sketchup, I don’t want to create any actual closed group, but it could be fine for it to be a thing where you just have to know to look in this forum to find, use, and discuss it. The script I have is quite old now, but let’s say I’ll look at it in the coming week, and see what I can come up with. If nothing else, it can serve as an example of how to directly write text-format bella files with no special libraries.