Version 1.1.6 - 11.26.2015
- Added Fan and Mod Queen common truss types.
- Structural outlookers (vert. & horz.) enabled under advanced roof options for Common (Fan & Mod Queen) truss types.



Four more common truss types still need to be added:

- Double Howe (6/6)
- Mod Fan (8/4)
- Triple Fink (8/7)
- Triple Howe (8/8)

For very large buildings one could also consider:

- Quad Fan (10/5)
- Quad Fink (10/9)
- Quad Howe (10/10)
- Quin Fan (12/6) ...

A quad fink truss (10/9) with a raised heel (slider):

Version 1.1.5 - 11.25.2015
- Added Double Fink common truss type.
- Structural outlookers (vert. & horz.) enabled under advanced roof options for Common (Double Fink) truss type.

Version 1.1.4 - 11.25.2015
Structural outlookers (vert. & horz.) enabled under advanced roof options for Common (Fink) truss type.
Structural outlookers (vert. & horz.) enabled under advanced roof options for Common (Fink) truss type with raised heel (vertical w/ strut).

Outlookers enabled under advanced roof options for Monopitch and Attic truss types.

Vertical structural outlookers with 12" overhang and 16" gable overhang:

A dropped top chord with flat orientation might look something like this:





Without an overhang the gable end truss becomes:





Note that the outlookers would probably be spaced from the bottom at 24" on center.

Outlookers get a little complicated depending on whether they are structural or not.  Typically around here we see them at 24" on center and they are usually structural.  The top chord of the truss is dropped either 1.5" or 3.5" depending on if they are oriented horizontally or vertically.  With structural lookouts the first lookout from the eave is usually non-structural since the dropped top chord truss will have a special slider attached to top chord to achieve the overhang. See image below:



Usually the sheeting goes on starting at the bottom so based on that the lookouts would be measured from the bottom edge of the sheeting so that they line up with the seams every 48".

I've seen a single vertical placed the ridge when the outlookers are vertical however what is common practice when the outlookers are horizontal?

Notice the different configuration of the top chord when the drop is only 1.5" (oriented flat).



If the overhang is zero then this slider or splice goes away.

Version 1.1.3 - 11.21.2015
Outlookers enabled under advanced roof options for Common, Scissor and Attic truss types.
Gable end trusses enabled for (2/2, 4/4) scissor truss types.

Outlookers enabled under advanced roof options for Common, Scissor and Attic truss types.




Not really sure what is the best treatment of the outlookers at the peak of the roof and consequently what is best way to space them.  Measure them from the peak or the eave/fascia?

One thing worth noting here is that structural outlookers are also enabled but I have not yet coded in the dropped top chord gable end trusses that would match structural outlookers, something for another day. Due to the option of vertically or horizontally oriented outlookers the configuration of a dropped top chord gable end truss can take two configurations. For attic trusses this gets even more complicated at the gable end, hence I haven't even attempted the gable end truss option for attic truss types yet.

The hot items on the todo list right now are:

- Tail Bearing Trusses
- Gambrel Attic Trusses
- Dual Pitch Trusses
- Rafter Roof (Gable and Hip)
- Valley Truss Set
- Hip Truss Sets

If you feel like something should take precedence over these items please advise.

Given the slopes of the dual pitch truss and the span calculate the distance between the left bearing and the peak:



However, you might notice that we are assuming the buttcut and top chord depth is equivalent for both sides.  If the slopes are different then this will mean that the heel heights will be different.  Should the heel heights be the same?

Version 1.1.2 - 11.16.2015
Metric input enabled for monopitch truss types.

I've also added advanced options for monopitch trusses (sheathing, rake and fascia).

Version 1.1.1 - 11.14.2015
- Gable end trusses enabled for all monopitch truss types.
- Added energy/raised heels for monopitch trusses (3 variants: wedge, slider and vertical w/ strut).


Currently there are only two versions of the monopitch truss available (2/2 and 3/3). 

The truss set below shows a monopitch truss set with gable ends and a 36" raised heel.

An interesting implementation of a straight line skeleton algorithm is at this link:

Actually let me rephrase that, any roof can get very complicated with intersecting roof lines whether it is framed out with trusses or more traditional rafters and beams.

If I incorporate traditional framing I would like for the user to be able to indicate the perimeter of the ext. walls and for the logic to be smart enough to handle any possible configuration.  Consider the custom home with guest house below:



Just to determine the proper placement of the ridge and valley lines requires some serious algorithms.  The technique I used to do it manually simply involves drawing isolines moving a fixed increment in from the ext. wall line.  These are really no different than contour lines on a topographic map.  The vertexes created by the intersection of these lines indicate the location of hip rafter, flying hip rafters and valley rafters.  When the isolines merge into one line then you have a ridge board.

This process is known as the straight line skeleton:

https://en.wikipedia.org/wiki/Straight_skeleton