I've been giving some thought to framed openings in floors, see image below:

Generally, at least from what I've seen most holes in floors are either rectangular, L-shaped or U-shaped, but I guess any outline is possible.
What I've shown in the image above is LSL or LVL framing out the opening however the actual framing might be significantly different depending on what is supporting the floor below.
In some cases the rectangular opening might not be supported by bearing walls from below, in that case the two LSL boards running parallel to the joists would probably be larger beams and the headers would be hangered from these beams and would also probably be more substantial.
The point is how to make this feature flexible enough to accommodate most framed openings but at the same time keeping it as simple as possible so the user is not overwhelmed with parameters.
View model here:
https://3dwarehouse.sketchup.com/model/a879f0c7-0900-47f5-9caf-acc1c3a53f25/Framed-Opening-TJI-FloorAny ideas would be greatly appreciated.
P.S. I am also going to make this feature editable so that the actual hole can be altered after the fact. This should be an interesting programming challenge.