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?

Various configurations of dual pitch trusses:

Various configurations of a vaulted or cathedral truss:

Floor trusses 40' span, 60' bldg. length, 24" deep.



Notice these are top chord bearing trusses with the diagonal webs reversed from the bottom bearing trusses in the previous post, this is by design.

Version 1.0.6 - 10.25.2015
Added floor truss type, Modified Warren - System 42.
Metric input enabled for floor truss types.
Top and bottom bearing option enabled for left and/or right end of floor trusses.
Ribbon cut option (top) enabled for left and/or right end of floor trusses.



One central chase that can be position relative to the left end of the truss.  If the chase becomes closer than 1/4 the span to either end it will flag the user and re-position.  Also some logic to check the chase size to span ratio and absolute max. chase size (24").

System 42 or 32 floor trusses using the modified warren configuration which seems to be the most popular for this type of floor truss.  Top bearing configuration includes an additional slider for extra strength and a vert. Note the change in diagonal directions when comparing a top to bottom bearing floor truss, I was not aware of this until studying them in some detail.  Typical panel length is 28" but this can also be set by the user to any value.

I figure if you need more than one chase it isn't to hard to manually edit the component and copy a couple of the vertical members over and then trim out the diagonals.

I've been adding truss types/families as requested by users and member of this forum and others. The list of families continues to grow and my current todo list is:

Common (tail bearing)
Dual Pitch
Gambrel Attic
Mono Scissor
Floor
Vault or Cathedral
Clerestory

Of course this is only a small sampling of the potential truss families and types.

Beyond the basic truss families I would like to have the plugin also have the option to generate gable end trusses for each family was well as all the raised heel variants (wedges, sliders and verts). The gable end trusses are more complicated than originally thought since structural and dropped gables also need to be included. Dropping the top chord 1.5 or 3.5 inches also further complicates the matter since this change in drop involves a different geometry.

Instead of dumping the trusses at the origin I've had requests for the ability to locate the truss array based on selection of a bounding rectangle. I need to give this some serious consideration since it will probably make this plugin that much more valuable and efficient to use.

I'm also thinking about more complex situations such as entire hip sets and valley sets.

Then there are transition gable end trusses and transition gable end monopitch trusses, which may or may not be worth adding.

On a completely different note I've also considered adding in timber framed trusses (ie. hammer beam trusses etc...) however I think a separate plugin dealing specifically with timber framing would be more appropriate.

I have no idea how long it will take me to accomplish all of this. I have become faster at adding truss types as I've settled into a standard procedure for adding each truss family. However, each truss family takes at least 2-3 hours to add in and then that only includes 1 or 2 configurations whereas I should probably add at least 4 to 5 configurations for each truss family.

I will probably continue to chip away at this as time allows and as interest grows.

As you can probably tell trusses are intensely interesting to me and that will probably keep me going regardless of the interest levels.

The equation was spot on, my faith in trigonometry is restored:



Version 1.0.5 - 10.24.2015
Added Scissor truss type, configurations: (2/2), (4/4).
Metric input enabled for scissor truss types.

In certain instances the scarf length of the bottom chord becomes less than the bearing length, the logic checks for these cases and inserts either a 3.5 or 5.5 heel wedge as required.