The point is that you should be able pull tape measure off the model and it matches what is in reality:
If you can’t do that, then the model is flawed or not detailed enough.
Version 3.2.6 - 06.22.2023
- Enabled the “Edit Truss Assembly” function for all gambrel attic trusses.
- Enabled a gable wall cut for gambrel attic trusses.
- Enabled a feature to selectively remove specific trusses from gambrel attic truss assemblies.
There are still a number of advanced options that need to be completed for this truss type, namely soffit and fascia need to be added.
The ability to edit this truss type is a fairly significant upgrade.
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Is that a pretty strong roof/second floor structure?
Looking at the truss more closely, the way it’s built looks pretty close to the way that we stick framed the “Oklahoma House” roof. Except ours had vaulted ceilings.
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Version 3.2.7 - 06.26.2023
- Fixed a bug with the truss removal feature.
- Enabled a feature to selectively remove specific trusses from common and monopitch truss assemblies.
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As some of you know I’ve been slowly working on incorporating some estimating capabilities for the Truss plugin.
Currently for a simple gable roof the estimating module (Project Plugin) will provide the length of the rafter as shown below (it will also provide lengths for simple hip roofs as well):
Note, that this is the total rafter length (ie. the length required of the board to fully cut the rafter). However maybe this specific length is not as useful as I thought it would be. What would the most useful length be? Or maybe two lengths? I’m not sure, I don’t work in the field actually building this stuff so I don’t really know what would be the most relevant and useful data to have with respect to rafter lengths.
I’m also going to make an option to enable FIS in the Project Plugin, just as I did in the Wall Plugin.
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For estimation / BOM, total length is the right measure. In my Excel BOM, I use total length to calculate the min. std. lumber length required and use that price for extended costs.
For parts that have the corresponding angle cuts on each end (in this case plumb cuts), I also spec chord length on the Cut List / Parts List as my check for cutting.
Here’s a parts list for a different application — overkill for your purposes — but the reasoning is similar:
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The top measurement is what we need for estimating. Total linear footage. Some people even report cubic footage, which might be easier for you from a logistical standpoint as I think about it. The total volume of all the members seems a lot less complicated to program.
The bottom two measurements are what we need to see in prints for cutting a roof. Also, what are the seat and heel cut on the birds mouth? Is there a parameter that drives the HAP? Can we manipulate it?
The question is, what does the framer really need?
Where you at framers? I helped frame but I’m not a pro. I just drew what the framer wanted to me to, and told him how long stuff was when the model was done. It would have been nice to not have to measure everything in SU. I don’t know how to draw proper plans, though I know how to use layout, as I’ve discussed elsewhere. 
Teach me your ways.
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It looks to me that five pieces of information might be useful to the framer, while only one piece of information is really useful for the estimator.
The estimator really only needs the total length of the required board. As we can see this is actually the rafter and tail length plus the additional amount due to the pitch of the roof. A soffit cut actually theoretically decreases this total board length some but I would not worry about that since you may have some variation or modifications on site with the exact placement of the soffit cut of the tail.
The framer on the other hand needs to know the total required length, the rafter and the tail as well as the HAP and the birdsmouth cut (seat and/or heel cut dimensions). Other information such as the roof pitch is also information that needs to be known but I’m mostly thinking about rafter specific data right now.
Rather than show all of these dimensions next to each rafter (will get too cluttered), it is probably best to just put them into some form of table.
Thoughts?
P.S.
I know that there is no real time API for Layout but is there a way I can create some sort of structure that can easily be brought into Layout as a table?
A temporary solution, if the name of each rafter had the Feet Inches 16th in it, for example, the name of a rafter was “12 - 7 - 13” (or however the majority opinion decided it should be formated) one could possibly use the leader text tool to click in a bunch of dimensions in layout since it would snag the entities name.
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Version 3.2.7b - 06.28.2023
- Fixed a minor bug with the truss removal feature for all truss types.
*Note: This is a critical bug fix for common, monopitch, attic and gambrel attic trusses.
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I love your commitment to this and the detail that has gone into it!
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What if somehow gable walls were aware of the roof settings and would update accordingly when changes were made to the roof. Like, if the pitch changes on the roof, the gable wall pitch would change with it? Just a thought.
I have no idea how difficult it might be to write the code that you’re writing. It’s impressive.
I think what I would like to see, if it is even possible, is some form of schedule or spreadsheet that has the material list (the length of the board you would need to order), the total board length, and also the rafter and tail as separate lengths.
I typically do all my roofs based off of ridge uniqueness.
Here’s one I did in Germantown Tennessee just outside of Memphis
It makes sense to me, but I would like to evolve what I do so that more people can readily understand the information so that a wider group of people can cut the roof.
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Larry and I have been doing proofs on a small 30’ x 20’ building to try and understand how to suggest corrections be made with chief architects framing. Here’s our typical building with the proper length for everything.
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Recalculated with an offset ridge (see previous discussion from the Project Plugin). As I suspected it does not change the overall layout of the roof, just the ridge placement and the amount to trim from each rafter to account for the ridge placement:
P.S.
This is basically the code to calculate and draw the rafters (point-for-point), once we have the roof peak x and y coordinates established all of the other coordinates fall out. The code does look a little different in Ruby so technically it is what one would call pseudo-code.
P.S.S
I just look at some of these equations and I think, “Wow! Math is such a beautiful language”. It’s almost like magic in how it can model real world problems, static and dynamic. One of these days I would like to try my hand at my own physics engine in SketchUp, or perhaps a finite element engine that can do structural matrix analysis, FEA or computational fluid dynamics. With the programming back end the possibilities are indeed endless with SketchUp.
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Planet Earth needs more math nerds.
I love your passion for accurately calculating material. I am going to enjoy spending time on this forum. I can see I’m going to learn many new things from all the great people here.
I think I’m going to have to take learning Ruby scripting much more seriously. This is what happens when motivated people associate with one another, it inspires excellence.
I’ve only created calculations for the different types of roofs I had to frame. I’m looking forward to seeing what other kinds of challenges people face, and maybe helping them develop ways to calculate them.
Here’s my roof types that I have equations for:
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Many times the framer is asked to do a take off for materials needed for framing. Any help in capturing all the structural wood members from joists, through studs, plates, rafters, and sheathing would be a very big help.
I’m adding to this comment since I seem to hit the 3 posts in a row barrier.
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https://www.dropbox.com/s/exlbilgn0dgxjhz/Mercedes_Roof%20Final.pdf?dl=0
More roof examples.
I’m hoping that with the collective design mindset here on this forum, a consensus can be achieved as to creating roof cut sheets that are clean and easily understood.
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Here’s another section/detail for a porch to main roof system.
I am thoroughly enjoying this thread. I love being around like-minded people seeking to max out their abilities. Larry Belk was a framer before being a full time designer. I really like the complexities in his designs…and he’s experienced enough to make them actually “buildable”.
It seems Nathaniel is also a seeker of the wisdom at the top of the mountain.
My old way of doing this is so antiquated compared to 3D CAD.
My old ways:
This is a stair string that prompts the user for the correct input to generate the right answers. The 3D was all in the users head…
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Toggling between centered and non-centered with an asymmetric gable roof:
Now I just need to take a look at the asymmetric hip roof and see if I can make it do the same.
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