I have also been researching vent blocking for trusses and I've seen a number of ways to do this both in practice and what is available within the code books.  Specifically blocking over braced wall panels becomes more critical and necessary but even for non-braced wall segments there is the possibility of truss roll over and I would highly suggest blocking in all situations.

Raised heel trusses further complicate the matter.  A number of resources I have found online that were interesting:

The SBC has a fairly lengthy discussion on heel blocking at this paper:

http://support.sbcindustry.com/images/technotes/T-HeelBlocking08.pdf

Raised heel trusses with large heel heights are given a "truss block" treatment.

However, APA paper SR-103A (2014) goes into some detail about using only the wall sheathing extended over the top plate in low wind speed areas.

The USDA has done some testing here:

http://www.fpl.fs.fed.us/documnts/fplgtr/fpl_gtr214.pdf

The heel blocking/bracing at heels of raised/energy trusses becomes more of an issue when a shearwall or braced wall panel is located beneath that segment of the wall line.

An article in the SBC Magazine:

http://www.sbcmag.info/article/2015/truss-blocking-panels

The 2012 IRC:

http://publicecodes.cyberregs.com/icod/irc/2012/icod_irc_2012_6_par055.htm

A paper that sums it up quite nicely:

http://smartgreenbuild.com/blog/download/519/

This was an interesting paper I have never seen before even though I subscribe to this publication:

http://www.structuremag.org/wp-content/uploads/2014/08/C-StructPerformance-Martin-Aug101.pdf

Many of the drawings and details in the CAD Library now require a Medeek Toolbox Key to download.  To make this more accessible I have recently added a 30 day access version of the toolbox key ($5.00).  Downloading of the PDF copy is still free of charge only the AutoCAD source file requires the key.

The link to the Medeek Truss Plugin is:


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


The link to the Changelog for the plugin is:


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

In the advanced options I would like to included the following options:

1.) Sub Fascia
2.) Sheathing
3.) Rake/Barge Board
4.) Vent Blocking
5.) Outlookers (Structural vs. Non-structural, Horz. vs. Vert.)
6.) Gable End Truss (Structural, Dropped top chord)

I think I will include the option for either of the 3 variants since it isn't too much more to code and I'm getting quite a mixed reaction from different builders and designers.  I guess everyone has there preferred method. 

Another quite common fascia treatment is to use a 2x6 sub fascia with a 1x8 finish fascia (primed spruce or cedar). 

However, I am mostly interested in the sub fascia and then I'll leave it up to the designer/architect to dress it up further as needed. 

I'm trying to make the roof framing as easy as possible and basic structural items such as trusses, fascia, outlookers are all automated, then the designer can concentrate on the finish work (ie. ridge caps, trim fascia, barge boards, cupolas).

I'm working on the advanced options for roof trusses and I'm looking at the fascia board.  I've come up with three different configurations for the fascia that I've seen in practice and in the architectural books that I have. 

Which method of the three below do you prefer?  or is there another configuration that I have missed?



Note that I am only interested in the sub fascia if there are additional trim boards that is up to the architect or designer.

As I've been contemplating adding gambrel attic trusses to the truss plugin I've had to give some thought to what constitutes a good gambrel design.  I've looked into this before but my conclusion is that no matter the lower and upper pitch of the roof a good looking design seems to be always achievable if the lower and upper legs of the roof are more or less equal in the length.  To that end I've devised a simple spreadsheet calculator that will quickly throw out the numbers and display a graphic of the gambrel profile:



I'm not saying this is a hard and fast rule but it seems to give decent results.  Minor variations (ie. L1 not equal to L2) are generally okay but if one leg is significantly longer than the other the gambrel profile becomes distorted. 

The math to come up with this equality and generate the coordinates of the overall roof height and the pitch break is rather interesting and for those mathematically inclined is given below.  Note that the equation ends up being a quadratic equation with the positive root extraneous:

Version 1.0.9 - 11.05.2015
- Added separate toolbar icons for floor trusses and joists.
- Created separate submenu items under the Medeek Truss Plugin Extension for roof and floor trusses.

The main menu was getting a bit cluttered and not so user friendly so I split it out into "Roof" and "Floor", hopefully this makes more sense.

I thought about multi-ply girder trusses but I think for now it is not too hard for the user to simply create another instance of the truss component and manually stack them up to create double or triple ply trusses.

Another interesting thought I had is what would it take to codify an algorithm for creating a typical dormer:



However, this may be a bit ambitious at this point but I think it could be done.

I'm considering adding the following advanced options to roof trusses:

1.) Sheathing
2.) Fascia
3.) Rake Board (Gable Overhang)
4.) Outlookers (Structural vs. Non- Structural, Horizontal vs. Vertical)
5.) Vent Blocks
6.) Gable End Trusses (Already in progress: Dropped top chord and structural variants)

This would then provide a fairly complete roof framing solution.

For floor trusses (adv. options):

1.) Sheathing
2.) Gable End Floor Truss (Ladders)
3.) Ribbon Board

For floor joists [TJI and dimensional lumber] (advanced options):

1.) Sheathing
2.) Midspan blocking at user selected bearing points.
3.) Sill Plate (for floor framing on top of concrete foundations)

Please suggest other options that might be handy to have.

Version 1.0.8 - 11.04.2015
- Added Weyerhauser TJI® I-joists: 110, 210, 230, 360, 560, 560D.
- Rim joist option enabled for TJI floor joists.





Only a rectangular configuration is available currently.  If I can figure out how to code a polygon version of this that would be much more impressive (ie. pick the points that define the perimeter of the foundation and the plugin generates the complete floor layout).

This is straying a bit from trusses but I figured if I'm going to include floor trusses I might as well make floor joists available as well, just a small bit of code to get there.

Version 1.0.7 took a while to pop out.  The big improvement is the ability to click with the mouse at three corners and place the truss set without any additional rotating or translating.

In literally seconds I can now put a floor and a roof on 4 walls using the truss plugin and the Homebuilder plugin:



Of course the gable walls are not quite right but you get the idea.  I may have slightly misunderestimated (a word created by GW Bush) SketchUp and what one can do with it.

The biggest hurdle was to learn how to create and properly set up a "tool" within the API.  Adding different truss types is much more fun than working through that mess. 

I'm also thinking it might be useful to have an option to put sheathing on the roof and/or floor?

I'm also looking for a good plugin that does stemwall and slab on grade foundations, if anyone has recommendations please advise.  I may use my own plugin for my own practice in order to quickly mock up certain structures and provide visuals.  With the right tools I think SketchUp can be a very effective and quick turnaround platform.

Version 1.0.7 - 11.03.2015
Trusses can now be positioned and sized via three mouse clicks, with the option for manual overide in the dialog windows.
The number of trusses is now based on the spacing and building length.
Floor trusses with top chord bearing now are positioned properly.


Hopefully I haven't broken the metric inputs with the latest revision.  I will test further tonight but so far its looking really good.

I've got gable end trusses working for king post trusses:



I haven't made this latest update live just yet as I need to update all of the other truss types to make sure it does not break anything.

The other thing I am changing is the second user prompt box that allows one to enter in the number of trusses.  I have now switched to a building length and the logic spaces the trusses based on the this length and the truss on center spacing.  Gable end trusses can be switch on or off.  Spacing of the gable studs is another user input.

Using the Medeek Truss Plugin and the housebuilder plugin I was able to create this simple model in about 3 minutes:



I would like to be able to create this type of model in the future:



This model was created in Solidworks and probably took a day or two to assemble.  Notice the gambrel attic and the gable end trusses.  That ability I would like to add into the plugin.

This next model was also created in Solidworks and only shows the foundation and framing, the entire model represents about a month of work including the drawing set.



I would like to see a plugin that is capable of generating this level of structural detail in a couple of hours instead of weeks.  Is this possible?

On a related note, does a plugin exist for creating SOG and stemwall foundations?