3D Truss Models
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As previously noted the web dialog from the plugin can actually be used external to SketchUp to explore gambrel attic geometry:
Imperial Units:
http://design.medeek.com/resources/gambrel/web_dialog_gambrel_attic.html
Metric Units:
http://design.medeek.com/resources/gambrel/web_dialog_gambrel_attic_metric.html
I might develop this into a web based app which would allow one to generate 2D AutoCAD geometry (.dwg) of the truss profile.
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With non-structural lookouts would you frame them something like this? This question is mostly directed at the contractors and carpenters out in the field who actually have to build these roofs. Typically as an engineer I never worry about these details especially when they are non-structural.
In my opinion they aren't really doing a whole lot, much better to drop the gable truss and then cantilever them from the first in board truss (ie. structural outlookers).
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Hip Truss Algorithm:
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I wish I would know what you're talking about, so I could help you. All this english roof terms are just... well foreign to me.
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Version 1.6.3 - 06.19.2016
- Added Gable Dormers to the Minor Roof Sub-Menu (dormer walls only).
For now only the walls of the dormer are created:
View model here:
https://3dwarehouse.sketchup.com/model.html?id=e17866e5-2e1d-4fb7-8203-fcb6484e8f08
I am still ironing out the details on how to best model the roof geometry. I will probably offer either a rafter or truss option. Other details such as multiple windows will also come later.
For now please test the metric and imperial wall creation. I will probably need to post a tutorial video on how to use this feature since it involves selecting the main roof plane (top of a rafter or truss) and then two points that define the width/exterior corners of the dormer.
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Medeek,
A 3D Kubity model may help viewers explore your 3D Models
(refer to private PM note)https://www.kubity.com/p/tWg5zg
[kubity:2u0sejcq]tWg5zg[/kubity:2u0sejcq]
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Outlookers oriented horizontally with gable end truss top chord dropped:
View model here:
https://3dwarehouse.sketchup.com/model.html?id=9f3dd430-1b90-435a-bfa6-f2bbe4d3e553
https://www.kubity.com/p/g2XGL2
[kubity:nam3sa03]g2XGL2[/kubity:nam3sa03]
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I like the ability to embed the kubity file directly, that makes it easy to view and convenient. The only downside is kubity does not display the edges so it is a bit hard to analyze the model fully. Is there a way to turn on edges in kubity?
The 3D Warehouse has the button that allows one to view the model in the 3D WebGL viewer, so to rotate and view the model in the browser is possible.
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Medeek,
I put your question to the Kubity forum on:
http://sketchucation.com/forums/viewtopic.php?f=400%26amp;t=65244%26amp;p=598242#p598242Discussion can be viewed here:
http://sketchucation.com/forums/viewtopic.php?f=400%26amp;t=65244%26amp;p=598268#p598268No definitive answer yet.
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Version 1.6.2 - 06.14.2016
- Added Symmetric Cathedral truss type, configurations: (AUTO).
- Metric input enabled for symmetric cathedral truss type.
- Added gable end trusses for symmetric cathedral truss type.
- Structural outlookers (vert. & horz.) enabled under advanced roof options for Symmetric Cathedral truss type.
Various sizes and configurations of a symmetric cathedral truss:
View model here:
https://3dwarehouse.sketchup.com/model.html?id=2755897d-3855-447a-bc13-d4478cf99355
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Testing the dormer (wall) feature out with a gambrel attic truss:
These dormers have a typical gable profile but it might be useful to have a gambrel dormer option as well to match with a gambrel style roof. Note that I have not shown all of the ladder framing in the model. On a roof like this it could get quite extensive.
To generate the dormer roof I just used my rafter roof feature and then trimmed the elements back manually.
View model here:
https://3dwarehouse.sketchup.com/model.html?id=315004e6-6c2e-427e-981e-dc891371c77c
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Same barn with a few more details. For gambrel attic advanced options I should also include the option for a crow's beak as shown in this model and the option to set the extension.
View model here:
https://3dwarehouse.sketchup.com/model.html?id=1d1a6c57-08c4-46a4-a93e-9ae28b9f477e
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@medeek said:
For gambrel attic advanced options I should also include the option for a crow's beak as shown in this model and the option to set the extension.
This would be a GREAT addition! Is there any logic to how far back along the main fascia that the crow's beak is supposed to merge in? Could this be an option along with the depth for the extension?
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Internal view:
Views will be available for Kubity in few weeksCrows Beak picture attached for clarity of term used.
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@mtnarch said:
@medeek said:
For gambrel attic advanced options I should also include the option for a crow's beak as shown in this model and the option to set the extension.
This would be a GREAT addition! Is there any logic to how far back along the main fascia that the crow's beak is supposed to merge in? Could this be an option along with the depth for the extension?
I hadn't thought this through enough. The logic for the crow's beak requires two inputs as you correctly stated:
1.) The extension length from the rakeboard measured from the exterior edge of the rake to the furthest point of the crow's beak.
2.) The merge distance along the main fascia where the crow's beak merges back into the rakeboard.
The logic to create this actually won't be that difficult I just need to get to it.
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Dormer Framing - Ceiling option
The attached image from:
Canadian Wood-Frame House Construction p. 148
http://www.cmhc-schl.gc.ca/odpub/pdf/61010.pdfshows ceiling for a flat section option. (ideal for services as electrical and other)
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The problem with dormers is there is a number of ways to frame them up. The way I like to frame attic dormers when using trusses is have the front wall rest on the attic subfloor and then the side walls rest on the truss top chord. I've also seen it where all dormers walls rest on the subfloor of the attic.
With a rafter roof that is open the entire dormer is often framed on the roof per facer's drawing (I call it a floating dormer).
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Under advanced options for gable roofs (truss and rafter) I am thinking about adding a "roof return" option. Any thoughts on "greek returns":
The images above shows a roof return with a gable termination, alternatively this could end with a hip termination as in below:
Or with a full greek which stretches across the entire span:
Does anyone have any specific framing details on how best to frame these roof elements?
As far as the logic to add them into the plugin it won't be a big deal, just an additional module that plugs into the advanced roof module.
To simplify things I would used the same pitch on the returns as on the main roof. The three variables would be:
1.) Return Type: Gable, Hip, Full
2.) Length of the Return
3.) Extension beyond Rake -
A quick study of a hip return:
Notice the inboard hip rafter does not terminate at the gable wall when the return length is too short. This poses some interesting framing given this situation, note the return on the right side of the roof is this case, not entirely sure how one would support/terminate the hip rafter in this situation.
When the return length allows the hip rafter to terminate at the gable wall then the framing is fairly straightforward.
The hip rafter will terminate at the gable wall when the return length is greater than or equal to twice the total return extension (Rakeboard Width + Gable Overhang + Return Extension).
The other question that I have is how to apply the sheathing to these small odd shaped roof segments. How far up under the overhang should the sheathing extend?
View model here:
https://3dwarehouse.sketchup.com/model.html?id=482d84f7-52a6-4b56-bf7d-4f373d825ec0
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This is an excellent link:
http://spot.pcc.edu/~rsteele/BCT122_123/return_eave.pdf
They run the outside hip rafter back to the gable wall and don't run the barge rafter (rake board) to the fascia like I've shown, maybe I've got this wrong...
This method would allow for sheathing of the return without having to notch around the barge rafter. I call this the floating barge rafter method:
Compare with extending the barge rafter all the way to the fascia board:
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