My wife kindly pointed out that the interior footing might not extend the full width or length of the building, very good point.  To correctly specify an interior footing you also need a start and end point, so five inputs total to define this feature:

Direction: X Dir or Y Dir
Footing Width:
Footing Depth:
Start: Measured from first selection point that defines foundation outline.
End:  Measured from first selection point that defines foundation outline, must be greater than Start length.

An example of a partial width interior footing:



View model here:

https://3dwarehouse.sketchup.com/model.html?id=c6935965-9939-43cd-b682-ffaf67a8a1cd

The problem with the basic UI is that it only allows for one interior footing.  If I webdialog this input menu I can show the layout of the foundation in plan view and allow for an unlimited number of interior footings as well as have footings running in both the X and Y direction.  The possibilities are really endless. 

The same methodology would apply for an arbitrary polygon shaped foundation.

Link to the plugin web page (under construction):

http://design.medeek.com/resources/medeekfoundationplugin.html

The toolbar icons:

Version 1.0.0 - 07.03.2016
- Created Medeek Foundation Plugin, utilizing SketchUp's Ruby API.
- Added slab on grade foundation type (rectangular outline only).
- Added garage curb and interior footing options.



View model here:

https://3dwarehouse.sketchup.com/model.html?id=1b5e9234-04a5-4e6f-bd4d-ec3006a2f6a4

https://www.qrvr.io/p/K7bzyt

The thing that would make this plugin particularly useful is if the user could define a polygon outline for the foundation, that will be next, then onto stemwall foundations.

12:12 main roof with a 8:12 hip roof return.  The interesting part is the hip rafter
where the return meets the main roof plane.  The dropped hip rafter is off center so that it supports the sheathing from both planes.  The calculations might prove challenging.

Version 1.6.4 - 06.27.2016
- Added roof return option within the advanced options menu for common, scissor and vaulted trusses, configurations: (HIP).



View model here:

https://3dwarehouse.sketchup.com/model.html?id=790b256d-72fe-46c9-b49c-dd7da0209a02

This option is available for most typical triangular shaped trusses.

I will be adding the gable and full return at a later date, currently only the hip return is available.  Another limitation is that the return roof pitches currently default to the main roof pitch.  I need to add some additional code that will allow the pitch of the return portions to be set independent of the main roof pitch.

This is an excellent link:

http://spot.pcc.edu/~rsteele/BCT122_123/return_eave.pdf

They run the outside hip rafter back to the gable wall and don't run the barge rafter (rake board) to the fascia like I've shown, maybe I've got this wrong...

This method would allow for sheathing of the return without having to notch around the barge rafter.  I call this the floating barge rafter method:



Compare with extending the barge rafter all the way to the fascia board:

A quick study of a hip return:



Notice the inboard hip rafter does not terminate at the gable wall when the return length is too short.  This poses some interesting framing given this situation, note the return on the right side of the roof is this case, not entirely sure how one would support/terminate the hip rafter in this situation.

When the return length allows the hip rafter to terminate at the gable wall then the framing is fairly straightforward.

The hip rafter will terminate at the gable wall when the return length is greater than or equal to twice the total return extension (Rakeboard Width + Gable Overhang + Return Extension).

The other question that I have is how to apply the sheathing to these small odd shaped roof segments.  How far up under the overhang should the sheathing extend?

View model here:

https://3dwarehouse.sketchup.com/model.html?id=482d84f7-52a6-4b56-bf7d-4f373d825ec0

https://www.kubity.com/p/ytJPd4

Under advanced options for gable roofs (truss and rafter) I am thinking about adding a "roof return" option.  Any thoughts on "greek returns":





The images above shows a roof return with a gable termination, alternatively this could end with a hip termination as in below:



Or with a full greek which stretches across the entire span:



Does anyone have any specific framing details on how best to frame these roof elements?

As far as the logic to add them into the plugin it won't be a big deal, just an additional module that plugs into the advanced roof module.

To simplify things I would used the same pitch on the returns as on the main roof.  The three variables would be:

1.)  Return Type: Gable, Hip, Full
2.)  Length of the Return
3.)  Extension beyond Rake

Same barn with a few more details.  For gambrel attic advanced options I should also include the option for a crow's beak as shown in this model and the option to set the extension.



View model here:

https://3dwarehouse.sketchup.com/model.html?id=1d1a6c57-08c4-46a4-a93e-9ae28b9f477e

https://www.kubity.com/p/uraGAJ

Testing the dormer (wall) feature out with a gambrel attic truss:



These dormers have a typical gable profile but it might be useful to have a gambrel dormer option as well to match with a gambrel style roof.  Note that I have not shown all of the ladder framing in the model.  On a roof like this it could get quite extensive.

To generate the dormer roof I just used my rafter roof feature and then trimmed the elements back manually. 

View model here:

https://3dwarehouse.sketchup.com/model.html?id=315004e6-6c2e-427e-981e-dc891371c77c

https://www.kubity.com/p/uCN2F6

Version 1.6.3 - 06.19.2016
- Added Gable Dormers to the Minor Roof Sub-Menu (dormer walls only).

For now only the walls of the dormer are created:



View model here:

https://3dwarehouse.sketchup.com/model.html?id=e17866e5-2e1d-4fb7-8203-fcb6484e8f08

I am still ironing out the details on how to best model the roof geometry.  I will probably offer either a rafter or truss option.  Other details such as multiple windows will also come later.

For now please test the metric and imperial wall creation.  I will probably need to post a tutorial video on how to use this feature since it involves selecting the main roof plane (top of a rafter or truss) and then two points that define the width/exterior corners of the dormer.

Outlookers oriented horizontally with gable end truss top chord dropped:



View model here:

https://3dwarehouse.sketchup.com/model.html?id=9f3dd430-1b90-435a-bfa6-f2bbe4d3e553

Hip Truss Algorithm:

With non-structural lookouts would you frame them something like this?  This question is mostly directed at the contractors and carpenters out in the field who actually have to build these roofs.  Typically as an engineer I never worry about these details especially when they are non-structural.



In my opinion they aren't really doing a whole lot, much better to drop the gable truss and then cantilever them from the first in board truss (ie. structural outlookers).

As previously noted the web dialog from the plugin can actually be used external to SketchUp to explore gambrel attic geometry:



Imperial Units:

http://design.medeek.com/resources/gambrel/web_dialog_gambrel_attic.html

Metric Units:

http://design.medeek.com/resources/gambrel/web_dialog_gambrel_attic_metric.html

I might develop this into a web based app which would allow one to generate 2D AutoCAD geometry (.dwg) of the truss profile.