3D Truss Models

medeek

Thinking about dormers today and attic trusses:

View model here:

https://3dwarehouse.sketchup.com/model.html?id=ud50cb83e-54fc-42b0-9b57-0a5691b1c678

2-ply girder trusses on each side of the dormer with ladder framing between. I haven't bothered to show all of the main floor framing geometry (doors, windows, stairs etc...) My question is what would be the best route for the infill framing above the dormers.

1.) Ladder frame perpendicular to trusses.
2.) Install a ridgeboard hangered between the girder trusses and a lower header and install rafters parallel to the trusses?

Note that the manual creation of the dormers took about an hour whereas the attic truss main roof and dormer roof were created with the plugin and only took about 5-10 minutes. I'm thinking a dormer routine would be useful.

medeek

I've been considering transition trusses and what it might take to add them into the plugin. Below is a quick study of this type of roof. I am curious to know if a common truss is butted up next to a transition truss for sheathing purposes. Also notice the scissor transition, this situation is a little complicated, not exactly sure how to deal with it.

View model here:

https://3dwarehouse.sketchup.com/model.html?id=ue1772e6a-eb97-4775-b9f8-d12e3e134ba3

For clarity I have removed all of the common trusses in the image below:

One question I don't have an answer for yet is what to do if the gable end needs structural outlookers? Has anyone ever seen a transition truss with a dropped top chord?

I think it would look something like this:

medeek

A basic algorithm to convert a common gable truss into a transition truss should not be to much problem. However, to make it handle all cases would become difficult if you include raised energy heels, drop top chords and scissor trusses in the mix. Consider the two examples below:

medeek

Version 1.4.3 - 03.20.2016

Added Scissor truss type, configuration: (6/6).
Added energy/raised heels for scissor trusses (2 variants: wedge and vertical w/ strut).
Addressed some minor usability issues with the scissor truss menu and options.

View model here:

https://3dwarehouse.sketchup.com/model.html?id=u8ca4bf44-f28a-481e-8c1e-b53de30e3696

I forgot to add in an example of a 2/2 Scissor Truss but that configuration also has raised heels available.

medeek

Polynesian 4/4 truss is working:

However, I haven't released this latest update yet, I still need to enable gable end trusses and advanced options for this truss type before it is ready for prime time.

The inputs are similar to all other truss types except you have two top chord pitches and a pitch break length measured from the left butt cut of the truss.

medeek

Version 1.4.4 - 03.21.2016

Added Polynesian truss type, configurations: (4/4).
Metric input enabled for polynesian truss type.
Added gable end trusses for polynesian truss type.

I'm not sure where this type of truss is commonly used but whenever I see one I think of a bus stop or train station:

View model here:

https://3dwarehouse.sketchup.com/model.html?id=u8fdab6c4-f7cd-4e4c-ae6a-d5add7e7ce76

Advanced options are not yet enabled for this truss type yet, so sheathing, fascia, rake will have to come later.

I haven't uploaded this latest version to the Sketchucation plugin store yet because I don't want to keep dominating the top spot so much. If you need the latest version it is always available on the web site. I will probably upload the current version of the plugin to the pluginstore about a week from today.

juju

wow, development just keeps on going, thanks!

medeek

After adding Bowstring and Bow Barrel trusses the only common other round truss type is the Barrel Vault. The problem with this type of truss is the webs get messy or at least hard to predicate because of the interplay between the vault and the pitched roof above it. In an effort to better understand this type of roof/ceiling configuration I've created the matrix below:

High Res. PDF copy here:

http://design.medeek.com/resources/truss/BARREL_VAULT/BARRELVAULT_STUDY1.pdf

I am trying to predict the max. height of the vault given a specific roof pitch and and vault width to span ratio. Perhaps I am recreating the wheel and some architect or designer has devised a method to create the perfect barrel vault given a roof pitch and other criteria.

I would be interested in what other opinions are on this matter.

medeek

Using a typical Barrel Vault 8/7+4 or 8/7+2 configuration I come up with the following triangulations. I'm sure there are other methods of configuring these webs but for the purposes of the plugin I think these solutions will suffice for now:

High Resolution PDF copy here:

http://design.medeek.com/resources/truss/BARREL_VAULT/BARRELVAULT_STUDY1_REVA2.pdf

Based on this matrix I've been able to come up with a simple algorithm for the triangulation of this truss type. I'll admit the barrel vault truss is one handsome devil.

juju

how's the manual coming along?

medeek

The manual is lagging behind the development. However, I'm thinking HTML UI inputs would be desirable with the ability to have pop up help dialogs for each parameter (instant help). The manual is still needed but it will change the entire look and feel of the plugin and make it easier to use in my opinion and easy to understand for the layperson.

medeek

A 9:12 barrel vault truss with a 16' wide barrel:

PDF:

http://design.medeek.com/resources/truss/BARREL_VAULT/BARRELVAULT_STUDY1_REVA3.pdf

The design of this type of truss is controlled by the following parameters:

1.) Out-to-out span
2.) Top chord pitch
3.) Barrel vault width
4.) Barrel vault radius

Assuming a typical web configuration as shown above the truss design is really only dependent on these four inputs. Minor details with regards to member depths, overhangs and ply thickness also factor in as well but don't really change much.

I can also see the possibility of running a raised heel variant but I don't know how common that would be.

medeek

Same truss as above but in SketchUp:

View model here:

https://3dwarehouse.sketchup.com/model.html?id=u93559996-8808-4186-9f65-3065a9d3f64f

medeek

Version 1.4.5 - 03.24.2016

Structural outlookers (vert. & horz.) enabled under advanced roof options for Scissor (4/4) truss type.

I guess I somehow missed enabling structural outlookers for scissor trusses. Anyhow this issue was brought to my attention this evening so I've tried to rectify it as much as possible. After delving into the code I realized that the scissor truss module needs a major rewrite and cleanup so I was only able to get structural outlookers enabled for the 4/4 configuration. Later next week I will jump back into this module and work on the 2/2 and 6/6 configuration.

medeek

I had someone ask me if it would be possible to create a small house or cabin based entirely on a raised heel attic truss profile, probably with some skylights for light. I've never seen this type of design before but I don't see why it might not work. Has anyone ever seen something like this done? Basically an attic truss with a raised heel (48') resting directly on a stem wall foundation with post and beams or something similar.

The one issue I could see is if there were no windows for a bedroom (no egress) that was midway the length of the structure. The design shown is 36' wide, 42' long with a 21' wide attic room. 6"x24" stemwall foundation, with a 12"x6" footing.

Typically large attic trusses are quite expensive so it would seem that this would be an expensive way to build a house perhaps there is some other reason that makes this method of construction viable?

View model here:

https://3dwarehouse.sketchup.com/model.html?id=u88dea626-2d7e-45cb-8751-6f2f3b101fc5

medeek

Another look at the cambered truss:

pbacot

Nice trusses with the arc shapes.

medeek

Version 1.4.6 - 03.26.2016

Added Cambered truss type, configurations: (6/X).
Metric input enabled for cambered truss type.
Added gable end trusses for cambered truss type.

Six variants of the (6/X) configuration dependent on the ratio of the camber width to span. Notice that in all cases the top chord has six panels, the bottom chord varies from 4, 5 and 6 panels.

View model here:

https://3dwarehouse.sketchup.com/model.html?id=ued7e0d19-2843-4b3a-9786-3c15cf876fdf

medeek

Second look at cathedral trusses (6/X) family:

The logic required to triangulate these type of trusses becomes tedious.

medeek

I've been meaning to add in cathedral trusses for quite some time and I finally had the chance last night. Configuration (3) shown below for a catheral 6/X truss:

Now I only need to code in the other six configurations and its ready to release as a new update.

View model here:

https://3dwarehouse.sketchup.com/model.html?id=u742d9d42-6911-4dc3-aa26-d5ad399b81e4