Quonset Gluelam Rib Construction (Not a Barrel Roof)


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Hi all,

 

I have been fighting with this for some time now and can't get it to work.  I upgraded to CA12 from HD Pro 20 in the hopes that the Curved roof functionality would work, but alas, I am still struggling to recreate this structure. This is for a renovation of an existing structure.  I drew up the ribs and quonset assembly in Onshape (Mechanical 3D design software. First two pics). The rib sits on a 2x6 sole plate attached to the top of the foundation stem wall. The rib arcs thru 65 degrees and then continues straight to a roof height of ~ 20' at approx 26 degrees. There is no ridge beam. I'm using two roof planes per side to create the curved section and the sloped section. I think I have tried every permutation and combination of setting in Walls, Build Roof and Roof Plane. Eaves are 5 1/5", gables set to 2". Last try was to make the first floor narrower by 5 1/2" on either side to see if I could get the facia board to sit on top of the foundation wall to mimic the sole plate. Wish there was a way to use the CAD function to draw the rib, place it and copy... I've lowered roof height 109 1/8" to try and get it to sit on the foundation wall, but I keep getting a stub wall that protrudes into rib creating a birdsmouth cut in rib. I have wall set to attic and made it invisible and birdsmouth turned off in Build Roof.  I was going to go with this until I tried to insert a Dormer for windows, but it said a wall was in the way. Now at a loss...

 

Any insights would be greatly appreciated.

Quon Assem.PNG

Rib Dims.PNG

Perspective.PNG

Framing.PNG

xsection.PNG

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22 minutes ago, DHunter7 said:

Wish there was a way to use the CAD function to draw the rib, place it and copy...

You can easily do this by drawing the CAD shape of the rib in section view, making sure it is a "closed" polyline. Then convert that to a polyline solid with the depth you need. It can be multi-copied, mirrored, etc. I do this all of the time for pole barns as well as metal buildings using free-span bents. You could probably do it with a 3D molding polyline but those are much more "finicky" to work with, especially if you have to edit them.

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5 hours ago, DHunter7 said:

Wish there was a way to use the CAD function to draw the rib, place it and copy..

 

the basics.....

 

Back clipped Cross Section through Hut > Cad Menu > CAD Detail from View > gets shape of Rib , make sure it is a closed Polyline ( fix if needed)  and Copy >paste/hold back into the Cross Section  and then convert to Polyline Sold  ( yellow Parallelogram with wand above it on edit toolbar )  then change the material to Wood/steel etc as P.Solids are always concrete when 1st built/made

 

this is a Vid. on a similar technique with P.Solids

 

https://www.chiefarchitect.com/videos/watch/10109/quick-tip-timber-frame-truss.html

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Okay cool... I will play with Polyline in xsect. How do I tell CA12 that it is a roof structure?  Do I put it on the Roof rafter layer?

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3 minutes ago, DHunter7 said:

Do I put it on the Roof rafter layer?

 

Yes you can do that, but it still will not be a roof rafter but at least you will be able to control it as one.  Much better than it being Cad Default.

 

You could convert it to a symbol which gives  you a few more options for inclusion in a schedule etc.

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6 minutes ago, DHunter7 said:

Okay cool... I will play with Polyline in xsect. How do I tell CA12 that it is a roof structure?  Do I put it on the Roof rafter layer?

 

Probably best as Chopsaw mentioned ........you should have X13 in your digital locker for download too if you just got Premier....

 

Mick.

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17 minutes ago, Kbird1 said:

P.Solids are always concrete when 1st built/made

 

In X13 you can control this at the Default level.

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I think Polyline Solids are the way to go.

Curved roofs will be a real pain trying to get the geometry and eave detail to work.

One big drawback with curved roofs is the max roof slope is 89deg - as far as I know you cant draw one with a 90deg slope which means it will never sit properly on a wall.

696021515_ScreenShot2021-07-07at2_42_49pm.thumb.jpg.aa27dcc614e965d2ce4a726903fcaabf.jpg

By the way, in X13 we have material (and other) defaults for Polyine Solids.

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Thank you all so much for the info.  I will check to see if I can upgrade to X13. Yes, the 89 degree thing is an annoyance...Curved roof seems to be a kluge that has limited value...

 

The reason I asked how to make a recognized roof structure is that I need to install shed roof dormers to add windows on the first floor. I may also want to put a couple of skylights in too higher op on the flat section of the roof.  Does the auto dormer or floating dormer tool require a known roof structure?  I presume so.

 

If I back section at the appropriate depths, I assume I could also draw in dormers using polylines?? 

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9 minutes ago, DHunter7 said:

I will check to see if I can upgrade to X13

 

If you SSA is current there will be and upgrade button to click , then you will see the download for X13

 

9 minutes ago, DHunter7 said:

skylights in too higher op on the flat section of the roof

 

They should work as you have Roof Planes but you may need to look into Manual Dormers in the KB ...I rarely use Auto Dormers these days btw, They won't be fun either way if Mansard and Gambrel Roofs are anything to judge by , but if you don't need "clean" 3D images of the interior it might be ok.

 

Mick

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3 minutes ago, DHunter7 said:

X13 installed.... 

 

Best to do your signature as some questions require different answers depending on the version in use....

 

M.

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