In many cases when you introduce a stairwell opening into  a floor like this it will be along the perimeter of the floor assembly as shown.  In these cases it is simpler to create your floor perimeter with the opening in mind:







Note, in order to create the additional gable truss (2x6 ply) I first changed my ply width to 5.5" then copied the gable truss at the interior of the stair well, then pasted it in place in the root of the model and then edited the floor assembly back to the typical 3.5" ply width.  Alternatively one could simply frame this small pony wall with the Wall plugin (ie. conventional framing) just as easily.

I'm not exactly sure how the trusses would work where the LVL beam/header is positioned at the start of the stairwell, obviously we would need some kind of header at that location.

Here is a link to the model for those who are interested in examining this floor truss example in more detail:

https://3dwarehouse.sketchup.com/embed/62200e55-7a11-4b43-bdac-4d00119d4f01?token=4RdrisG1fJM=&binaryName=s21

Version 1.0.8 - 06.08.2025
- Updated the SUBTRACT and SUBTRACT_JOIST features so that they can better handle MPC wood trusses, steel trusses and open web "Redbuilt" trusses.
- Updated the Floor Opening module so that it can handle MPC wood trusses, steel trusses and open web "Redbuilt" trusses.
- Added a "None" option for the header type in the draw and edit menus for floor openings.

Version 1.0.7 - 06.06.2025
- Enabled MPC Wood Trusses with ribbon boards, multiple chases and gable trusses.
- Updated the Move Floor Edge tool so that it also toggles the metal plate connector layer.
- Update the SUBTRACT_JOIST feature so that it can adequately handle MPC wood trusses.

Tutorial 27 - MPC Wood Trusses (13:25 min.)

Looks like I'm about 95% there with floor trusses:



The only issue appears to be what happens when ribbon boards are enabled and you have an inside corner as shown. I probably need to add in some additional logic to eliminate the slot for the ribbon board in these cases.

Just when I think I'm ready to move to the gable trusses and the ribbon boards I realized I hadn't checked top bearing trusses. Spent most of yesterday and this morning sorting this truss geometry out:



I've spent a good bit of time devising the algorithm that inserts the webs into these trusses and overall I think it is fairly successful (and believable) however I will be the first to admit that it is not quite perfect. Also I am little unclear on how to deal with specific situations. I guess I should spend some more time studying different Mitek and Alpine floor truss examples to cement my knowledge on the exact way all cases are handled (even though there is probably some variability in certain instances).

After a full day of tinkering and refactoring a bunch of the original floor truss code I think I now have the multi-chase algorithm working:



Note how the chases all line up even though there are five or six different truss profiles within this assembly. I still need to create the web generator between the central sections of the truss profile, there is quite a bit going on here. I am still a few days out from completing the programming and then another two or three days of testing and further debugging.

First look at a polygon floor using MPC floor trusses.



However the following the items still need attention:

Gable trusses
Ribbon boards
Multiple chase locations

Version 1.5.2 - 06.02.2025
- Updated the wire library to include all the common NMB wire sizes.





This update per customer request.

Wire sizes per the Southwire (Romex) documentation:

http://design.medeek.com/resources/electricalplugin/references/2403_3-C_Romex_NMB_Cable_SpecSheet_Web.pdf

Version 4.0.2 - 06.01.2025
- Added a bottom gap parameter to the draw and edit menu of the door module.
- Added the bottom gap parameter to the door tab of the global settings.

Tutorial 26 - Editing Opening Headers (5:00 min.)

Version 1.0.6 - 05.31.2025
- Added an edit function to the "Stretch Floor Header" tool.
- Added a "Timber" header type for floor openings.
- Fixed minor bugs in the floor opening module.

Version 1.0.5 - 05.30.2025
- Added the ability to stretch opening headers with the "Stretch Floor Header" tool.

Tutorial 25 - Stretching Opening Headers (7:50 min.)

Here is a quick mock up of a window wall in SketchUp (circa. 2016). This is before I had the wall and foundation extensions completed, however the roof was actually drawn using the Medeek Truss plugin (that did save me some time). This model helped visualize what was going on with this specific design and also helped me quickly realize that there were some areas that needed special attention.



The room below the window wall was actually just a rather tall crawl space but note how the load path of the in-wall columns extend down through the crawl space wall and then the resulting spread footings below them. The columns are supporting the roof glulam beams and as a result are relatively loaded.

Notice the rear wall and how many openings it has, a bit tough to make this design actually work (shear). I also ran into my first real encounter with interior shear walls. With interior shear walls it is important that they extend up into the attic space and complete the load path with the roof diaphragm.



I've also attached a related shearwall fix where the contractor did not initially include a double sill plate. Physical, on-site inspections of the framing were always a requirement, a lot of the times there were quality or other issues that needed addressing. Or in some cases the contractor did not fully understand the intent or requirements of the structural plans.

Before I ever ventured into the plugin development world I did quite a bit of residential structural work. Since then I've pretty much switched hats and now my entire focus is on the extension development.

As a resource to other designers, architects and engineers I may occasionally post a few examples of structural work I've done over the years. Most of this work was done about 10 years ago. Note that I've removed any private or identifying information. Additionally these examples are for Educational Purposes ONLY and are not intended as a specific engineering solution for any other project or plan. Let me know if any of this is helpful or useful and I might be inclined to post a few more examples.

Here is a simple braced wall plan detail: