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.
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.
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.
Structural outlookers for this type of a roof are still somewhat of a question. If they are horizontal it makes sense to notch the gable rafter but what if they are vertical?
It is amazing how many variations there can be for trusses, I believe it to be infinite, therefore a plugin will never do every roof type for trusses without it being very complex and difficult to use ( I do not think that a consumer product would be feasible enough pay for the development cost tp cover 99% of the industry). The other thing that I can see that may be an issue is that trusses are engineered systems that relate back to manufacturers of metal connectors, so the variables are many. Most builders and carpenters simply send the plans to a truss manufacturer and they detail these mostly for free (basically the manufacturer absorbs the cost in the manufacturing). Really the only benefit to having trusses in Sketchup is for visual reasons in section cuts and visual clash detection with Hvac/ MEP.
I had a quick play with the drawing there are a couple of things I noticed.
I may be missing a dimension as it I cannot determine the length of the wall parallel the 2566 long wall to without tracing over the plan.
Regardless I took a look and this type of truss configuration and it can be automated. yet the Skylight is another kettle of fish.
In short the innumerable variations of design across the world will always come up with a problem that had not been considered. 95% of construction is similar (Square, hip, valley and gable construction) This will all be added into Plusspec in the future, we have been working on it now for some time. I personally think that Medeek is doing a fantastic job.
Anyhow this is a screen grab of a 2 minute truss config from the info you provided, it is currently buggy and personally I would not build from it or estimate from it. … and I know the hips are not in the right position on the skillion section, I did not have the correct measures or time ATM.
The configuration are infinite however I think one can program 95% or better of the most common cases. Everything else has to be drawn manually. How did you generate the geometry in the image shown? I’m looking at hips rafter framing right now and I am having some difficultly with the beveled cuts where the hip rafters intersect with the ridge and fascia.
Notice in this case I have left the gable rafter in place but notched clean through it, so essentially it is blocking. However, I have also given the option for removing the gable rafter entirely. You will also notice that the gable rafter is the same depth as the outlookers, when you choose “CUSTOM” for the gable end rafter it allows one to specify the depth of this rafter.
When structural outlookers are used in a vertical orientation it is common practice to have them bear directly on the double top plate of the gable wall (balloon framed to roof). If there is some configuration that is standard in your neck of the woods that I am missing please let me know. I am currently providing three different configurations for the gable end rafters.
I think I am ready to now attack the gable rafter roof with glulam beam.
The above geometry was generated with PlusSpec Alpha it is not public release as yet as it still has a few bugs to iron out. Plusspec 2016 may have a rudimentary version for testing in the first release as we have a few other priorities.
The hip and bevel cuts were a challenge, just to be clear I did not code it as I am a builder and designer, I simply pay the developers in my office to do it.
Agreed: 90 to 95% can be done, yet Girder trusses, recessed ceilings, skylight wells, internal load bearing walls and connections can be problematic as there are many way to do the same task. I think the key is to look at time on sight versus, cost of lumber, versus manufacturing time. Regardless everyone likes to do things differently. I try and keep most of the people happy most of the time.
I sent you an email, I apologize for the interruption on the thread, I replied to an individual post on Gadget2020 yet the reply went to base. I can take it down if it helps?
I have a question on the structural outlookers, (we call them outriggers in Australia, yet we call toilets Dunnies and alcohol ■■■■ ) The last outlooker is short just above the top plate which means the barge board and fascia are cantilevering to hold the corner of the roof. Why is this,it has been a while since I was on the tools… I imagine it is due to the gutter holding more weight in water than the barge?
Admittedly the user interface is still very rough around the edges. One thing I’ve started working on is making the default values assume the last values inputted by the user. The code is fairly simple but updating all of the different menus is tedious because I have quite a few truss types now. This should make creating multiple truss sets in a document even quicker since parameters like roof pitch, overhangs and heel heights are typically the same for a given structure.
To test this functionality currently, download the latest version 1.1.8 and test the common truss types (Imperial Units). I will be updating all menus so that this functionality is present.
With regards to the configuration of the outlooker near the outside corner of the roof, to be perfectly honest I’ve actually never given it too much thought other than I’ve always seen it framed that way. I suppose one could frame a diagonal outlooker to fully catch the corner but in that case then the other two would be cut short. My theory is two fold:
1.) As you suggest the weight of the gutter and rainwater make the eave more heavily loaded.
2.) The sub-fascia is being supported by the rafter tails which is turn is holding up the lower end of the barge board. As such I would think one would want to provide support for the sub-fascia as close to the corner as possible.
The corner could probably be framed out either way, one of the boards ends up getting cut and does not provide much bending resistance.
Another thing worth noting is the rafter tails (with large rafters as shown) are usually trimmed to the bottom of the fascia or slightly higher and then a closed soffit is attached. Since the rafters are components it is very easy to go in and make this trim cut to all the rafters so I leave it to the user to make this modification instead of another option.
On the same token the ridgeboard would probably be trimmed as well. I need to look at that a little closer.
Thanks for running through that, however one main design issue you may have over-looked is that the ceiling tie is raised. (there are a couple of other minor things too, but that’s the main one i noticed)
The drawings I posted are from our truss manufacturer and are what will be delivered to site for installation - he got supplied with fully dimensioned CAD plans to work from (not SU it must be said.)
We sometimes use these to generate a SU model to put onto the drawing for the joiners on-site (on occasion it’s easier to see how things go together in 3D rather than from the truss layout.)
And I agree: Medeek is doing great.
Another thing (other than rooflights) that is common to our construction is that the new extension gutter line is lower than the existing house gutter line, so the back-on dormer is raised (ridge line runs through, valley is shorter).
We also have a popular design that is similar to Medeek’s Gable Roof where every second/third rafter has a raised ceiling brace/tie. (Insulation gets placed between the rafters and the exposed tie gets clad with finished timbers)
The rafters with the ties on them are doubled up - normally the tie is the same material, but it’s rough timbers and the ties are plate jointed to the rafters. This is why we clad it - it also means we can match the window cills & skirting boards. This is our show site (Aberdeen, Scotland - so it has to withstand quite a bit of wind sheer and snow loading). This went up 2/3 years ago and I would guess that about half the extensions we have done since then are of a similar nature - it’s a really nice room.
The front face is supported by 100mm vertical flitched posts (steel sandwiched between timbers), but the rest is just timber. The window frames just fill the holes and lend no structural integrity. What you are seeing is 6m wide, the glass is 3.2m tall with a 0.6m high dwarf wall and a 30º roof pitch. (0.2m overhang on gable and eaves.)
We occasionally do the same thing without the ties, but this would involve a steel ridge rather than timber.
Adding in ceiling joists is not a big deal but I don’t want to add features that only complicate the plugin and the user experience. I could also make an option to offset the ceiling joist off of the wall top plate for a “raised” ceiling joist if this is something that would be useful
It looks great and the raked ceilings really up open the space.
We call the horizontal member collar ties down under, it is a big call to do with a truss as the tail of the rafter can push the walls out if the timber deflects. I assume they would be using a laminated veneer lumber in this instance or F27 hardwood.
I would usually draw this type of roof with the rafter tool and then add the collar ties in. I guess it depends on how much detail you like to go into. I do quantity take offs from my models so I can keep a track of the cost to the client. One of my biggest gripes is redesigning due to budget restraints. It does not look like the client had a tight budget on that job, nice work.
) The last outlooker is short just above the top plate which means the barge board and fascia are cantilevering to hold the corner of the roof. Why is this,it has been a while since I was on the tools… I imagine it is due to the gutter holding more weight in water than the barge?
