Development and Updates for the Medeek Truss Plugin

[Medeek]

- Enabled metal plate connectors for floor trusses.



View model here:

https://3dwarehouse.sketchup.com/model.html?id=ec5402ad-0916-46f7-a84d-1bf7e57ed30f

[Medeek]

Looking through some old plans I've managed to dig up I came upon a couple of designs by another engineering firm. 

Typically when I've dealt with truss designs I always seen a scarf cut on the bottom chord with the top chord remaining un-notched.  In this other example the bottom chord is kept intact and the top chord is scarf cut or notched, while still allowing a continuous section to extend for the overhang with a depth equal to at least 1/2 the top chord depth.  I think the picture below explains this far better than I can with words:



For MPC trusses I am used to seeing a 1/4" butt cut, however for timber trusses what is more appropriate?

Which method above would go with (arch. and structural reasons)?

View model here:

https://3dwarehouse.sketchup.com/model.html?id=6d3633a4-3b5c-4b9f-9780-23be5230c66d

[Medeek]

Plates applied to the top truss:



Specs:

- Truss Type: King Post
- 6x10 TC, 6x8 BC, 6x6 kingpost
- Plate thickness = 0.25"
- single row of bolts with two bolts per row.
- connector plate width = 4.0"
- Bolt Dia. 3/4"
- Bolt Edge Distance (timber) = 4.0"
- Bolt Edge Distance (plate) = 2.0"
- Bolt Spacing = 4.0"
- Bolts and Washers not shown. 

View model here:

https://3dwarehouse.sketchup.com/model.html?id=ed8f688c-a1a2-4c2a-b09a-8ee937060922

[Medeek]

This particular joint on a gambrel attic roof I am finding particularly difficult to plate:



Luckily I have a few samples to use as guides.  Given my web configurations at this joint this seems to be the most reasonable method to plate this joint.  Note that the plate  should touch the interior corner and the exterior of the lower top chord but at the same time not project past the lumber into the spaces.  Also the plate is rotated so that it is parallel to the upper top chords pitch.

The algorithm I devised to do this is quite clever I think but can be boiled down to a few concise lines of code:

     

Code Select Expand

  # Plate 2 (Gambrel Left)

x2 = @W2x2 - (mpcyy)/(sin(@Phi2))
y2 = @W2y2
m2 = tan(@Phi2)

x1 = @X2
y1 = @Y2
m1 = tan(@Phi1)

x0 = (y2 - y1 - m2*x2 + m1*x1)/(m1 - m2)
y0 = y1 + m1*(x0 - x1)

xoffset = (mpcxx/2.0)*(cos(@Phi2)) + (mpcyy/2.0)*(sin(@Phi2))
yoffset = (mpcxx/2.0)*(sin(@Phi2)) - (mpcyy/2.0)*(cos(@Phi2))

mpcx = x0 + xoffset
mpcy = y0 + yoffset
mpcrot = -@Phi2
MedeekMethods.metal_plate mpcx, mpcy, mpcxx, mpcyy, mpcrot, "PLGL"


# Plate 2 (Gambrel Right)

mpcx = @X5 - mpcx
mpcy = mpcy
mpcrot = @Phi2
MedeekMethods.metal_plate mpcx, mpcy, mpcxx, mpcyy, mpcrot, "PLGR"

This joint has been the most difficult so far, everything else has been cake.

[Medeek]

Version 1.7.5 - 12.24.2016
- Enabled metal plate connectors for valley truss sets.
- Enabled materials and custom layers for valley truss sets.



Merry Christmas to all.

[Medeek]

Version 1.7.6 - 12.26.2016
- Enabled metal plate connectors for monopitch trusses.
- Enabled materials and custom layers for monopitch trusses.



View model here:

https://3dwarehouse.sketchup.com/model.html?id=40819b39-458c-4e87-8a5e-fe16982dfe1d

[Medeek]

Version 1.7.7 - 12.31.2016
- Enabled materials and custom layers for gable, hip, shed, TJI and dutch gable rafter roofs.

[Medeek]

Version 1.7.8 - 01.02.2017
- Enabled materials and custom layers for gable dormers.
- Added advanced options for gable dormers, enabled exterior wall sheathing option.



View model here:

https://3dwarehouse.sketchup.com/model.html?id=5b255dad-4823-450d-a7d9-153d983e73a5

[Medeek]

This is an example of custom layers and materials implemented in the Medeek Truss Plugin and Medeek Foundation Plugin and used in one model:



View model here:

https://3dwarehouse.sketchup.com/model.html?id=5ff9d1dc-7384-4c7f-bc8a-915c2cd3fc6c

Turn off the sheathing layers first to reveal all of the structural framing etc...

Regular walls were created with the Housebuilder plugin.

The trim tool in the Truss Plugin was used quite successfully to manually trim back the dormer roof framing and sheathing.

[Medeek]

Spent some time this morning traversing through the common truss code updating some of the truss types so that I can enable energy/raised heels for all common trusses as well as enable custom layers, materials and connector plates. 

As I've developed the plugin and added new features I used the fink truss as the cutting edge, so everything having to do with this truss type is pretty much up-to-date, however some of the other truss types are seriously lagging so a little house cleaning is in order.

It may be a few days before I can release this latest version since there is a lot of tedious work ahead.

[Medeek]

Raised/Energy heels add another level of complexity to the equation.  Below you can see that various heights of a raised heel on a simple King Post truss requires different configurations and hence separate plating routines:



This also affects the gable trusses as well, below is a fink truss with its gable counterpart:



View models here:

https://3dwarehouse.sketchup.com/model.html?id=91d8d78a-8e6c-4dab-9839-4d689c84c297
https://3dwarehouse.sketchup.com/model.html?id=89739563-049f-4277-bfca-75663724967e

I'm still house cleaning.  I've now got the King Post and Fink truss fully cleaned up with connector plates enabled for all possible configurations (raised heel, non-raised heel, structural, non-structural).  I've only got 10 more common truss types to work through, see list below:

Queen Post
Howe
Fan
Mod Queen
Double Fink
Double Howe
Mod Fan
Triple Fink
Triple Howe
Quad Fink

[Medeek]

Version 1.7.9 - 01.15.2017
- Enabled metal plate connectors, materials and custom layers for the common king post and howe trusses.
- Added energy/raised heels for howe truss (3 variants: wedge, slider and vertical w/ strut).
- Metal plate connectors now enabled for king post, fink and howe raised heel/energy trusses.

[Medeek]

I'm still investigating "real world" applications of the plugin to determine where the weakness and deficiencies are.  Here is an example combining a dutch gable rafter roof with some raised heel trusses.  Now that the raised heel feature is fully active for many of the common trusses it is actually quite easy to measure and then match the heel height of the rafters.



View model here:

https://3dwarehouse.sketchup.com/model.html?id=461e63b6-4965-4697-b864-a9fbe464d53a

I am interested in how others are actually using the plugin and where it is falling down for you, please feel free to send me models or post on the forum with your "real world" design issues with regards to the plugin.  This will help drive future development and prioritize the more important items on the todo list.

[Medeek]

Raised heel double fink truss with connector plates:



I added this one today and will roll it into verson 1.7.9b.

[Medeek]

Another item I have been putting off is the heel blocking.  I'm planning on offering two variants (vertical and angled), with the option to draw in the ventilation holes (typically 2" in diameter in my region, with 3 holes per 24" o/c spacing) if desired:



Obviously this is not a hot item since no one has bugged me about it but I have not forgotten it, just put it aside up until now.

With raised heels this may become a bit more complicated requiring more options, (ie. a V-cut instead of the typical bird holes).  More input from builders would be useful in this regard.