Here is an example of a large valley set with a Monopitch Primary Roof and a Common Secondary Roof.  Notice the pitch of the monopitch roof is 6:12 while the secondary roof is 12:12.



Rather than calculate the overhang for the secondary roof it is just as easy to to trim the truss tails back and adjust the fascia so that it lines up with the fascia of the main roof after the fact.

Even with all the automation of certain tasks there is still a good bit of manual editing required when complex roof lines are involved however I find that SketchUp has a very intuitive interface for trimming solids and once the basic geometry is there the rest is usually not too much trouble.

This update was not that complicated (valley sets) other than trying to figure out how to place the set based only on a plane and two points. Obtaining this information and then figuring out the math and code to compute the vertical distance between the bottom of the first valley truss where it rests on the main roof plane and the peak of the secondary roof line was the slightly painful part. The actual geometry of the valley set was surprisingly easy to code.

The real challenge will begin when I try to add some hip sets, I may push that out for awhile.

I've addressed a few bugs with the valley set algorithm and tested it in as many configurations and orientations as possible.  It it more solid now.  I suggest downloading the latest version of 1.1.7 that I just uploaded to the server.

Note that the plane of the main roof that is selected needs to be a rectangular shape at the moment to properly register (1st point selected).  I usually just select the top face of one of the top chords of the trusses.  The second point should be at the centerline of the last truss of the secondary roof line and at the ridge (peak) of this truss, the third point is also at the ridge (peak) but at a point towards the main roof.  I really need to put the manual together to document this feature and how to use it, or at least a video. 

I also updated the geometry algorithm slightly so that it adds additional verts a 48" o/c when the valley trusses get too large.  This is keeping in line with standard practice on these types of valley sets.  I can also make this an input if someone requests that it be such.

Valley Sets are here:



Proceed with caution though I just put it together so it is still a bit rough around the edges.  Further testing and refinement is necessary but it seems to be working fairly decently.

Currently the main roof plane and two points need to be selected rather carefully I'm not sure I can do much about that, if not I will need to document in some detail how to use this function.

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.