Off Center Reciprocal Roof Framing
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I've designed myself into a bit of a challenge. Have found some good, but old youtube vids about reciprocal roofs. My design, however, has the opening in the roof off-center. I have no idea if this could happen structurally, but it seems that it must be possible to at least construct in sketchup... provided each structural member has a specific angle.
In the attached file, you will see my intended roof form, the flat geometry, and the structural components ALL at a 45 degree angle. Of course, due to the off-center opening, the components do not meet each other.
My question is more a question of math/geometry: how would I calculate the angle of each component in order to make them all hit each other at the top opening?
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The base circle of the truncated cone at the axes origin is not horizontal.
Is this on purpose ?
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Hi Jean. It is intentional. However, it is likely easier to construct the thing using a horizontal circle, and then rotate that circle, and extrude the individual members afterward, no?
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I would guess so, and the same for the smaller circle too.
I just played around and got to create this SU file. Click in sequence on the Scenes tabs.
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JOHNNY! That's awesome! I was coming up with the same math, but simplifying it to lines as you did sure makes it much easier to comprehend.
The project I'm working on is due in presentation format tomorrow, so I won't try re-doing this until after it's submitted. However, if my project is selected, I may float this concept by an engineer to see if it would fly. With some cross members, I wouldn't see why not.
Thanks! (Fun little geometrical challenge, huh?)
Have you worked on many reciprocal roofs?
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Share some pictures of the finals?
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I have never worked on such a roof, neither on any roof as I am a mechanical engineer specialized in piping.
My experience with SketchUp (SU) dates back from more that 15 years when SU was at version 3.0 and I always enjoy trying to solve geometric challenges.
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Jean, I know a carpenter that could put it all together. Only problem is that he is locked up in an asylum at present! I understand the last complicated roof drove him stone mad
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Hi Mike, hi folks.
That's a good one.
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