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Can this roof be built in real life?


Cesar R
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The reason I ask is because I can not get the top ridge to be straigh or paralell to the ground when I build it in Revit. It is always slanting towards the font.

so i modeling it in 3dsmax and I just can not understand why I can get it to work. some people sugested that maybe this roof can't be built and therefore it cant be modeled in revit using the roof tool (I dont want to fake with a custom family) so please advice

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Frank Ghery has proved that you can build any shape.

 

But just looking at your plan its obvious that the rectangular portions on either side of the center triange are not going to be planar. The top line must be parallel to the bottom line. You could build it by allowing a triangle (in plan) at the top, or accepting a warped surface (which doesn't sound like a very good idea).

 

I'm sure some of the real architects here will have more specifics for you.

 

Having re-thought that--of course your bottom and top lines do not have to be parallel to define a planar surface. It just has to be a planar surface, and most 3D programs will allow you to abuse polys until they are NOT planar.

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This can be built in real life and certainly in Max. As far as Revit, I don't know but just another reason I recommend doing all modeling in Max. It's clearly not a standard roof, but I don't know why it would be difficult making it work in Max. Just go to Edit Mesh Vertex subobject mode and move the welded vertices around as needed.

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You could do that in Sketchup :)

 

Can you just make the plane of the bottom of the roof, and planes of the parts of the roofs, in whatever 3D modeling program, and intersect them to see what they do? I think Ernest is right - Revit is making the planes planar, and when it intersects them they make that diagonal line. Max is doing it the way you want but not in a constructable way. Is this something you're building (you need to get it right), doing visuals for somebody else (it needs to look the way he wants it to) or a school thing (it just needs to look good and make enough sense that you can use it to talk theory, unless it's a building systems class)?

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LOL,

I can say with great certianty...yes it can...now finding a good framer that wouldn't F/U royally is another story.

Your image from Max, however IS NOT repeat IS NOT what is drawn in the plan view. Make sure you have it striaght in your mind, Max and on paper or you WILL have problems when it gets built.

I framed a roof just like that 3 fricken times, count 'em three times. Why because the Architect or his flunky drew it wrong. Built it by the prints....looked like crap was told to do it again another way by the expeditor. Told him point blank that was not right....he's the boss OK. It was still wrong. Met with the the architect, because of course what does a fricken carpenter know..... I was right, architect saw right away the drawings where wrong. Moral of the story got paid to build it three times and the Architect paid for two of them ;)

Sorry if this post is over the top... your doing it right asking to make sure it can be built :) Just make sure it's right all the way around, please LOL

WDA

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Ceasar,

 

Here's the skinny with these funky roofs. What you are doing by adding a ridge at the top of the dormer roof is creating a reversed roof facet, with a pinch point in the valley at the fascia. That being the low profile dormer roof. In essence that reverse facet is a 'common' dormer roof with a faceted hip at it's end. It can be built like that easily "on top of" a common (main) roof. If the interior is vaulted you have a number of issues. The biggest one being the frame/load point fo the valley rafter and the first hip rafter technically being at two different pionts in 3d space. That will always create head scratching amongst the trades....this is exaclty the same issue I mentioned before.

 

Getting anything 'AutoDesk Cad' to create it accurately is another story completely. I don't have revit...but from what I understand it's the same issues as ADT to nake it work, because of the pinch point/reverse facet. It has to be two seperate roofs. Simply because the roofs have different hieghts above the walls caused by different slopes. The common dormer (reverse facet) can be calculated at the wall, the hip roof has to be calcualted at the interesction with the facsia, then the interesection/hieght above the wall at the load bearing point for the first hip rafter out....and that's what I see in your revit rendered view.

 

I'll take a look at the cad file....I'd suggest just modeling/remodling the roof in Max based on the fascia/roof intersctions and the valleys-ridge as you have drawn them.

 

WDA

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Okay,

 

Thanks for uploading the file. I took a look at it and I attached a revised profile for the bay window roof.

 

One of the errors I found was the roof angle that you were using on the roof plan. In order to maintain the same roof pitches, the intersection would be at a 45 degree angle. Your angle was set at 56.32 degress, it appears.

 

Anyway, it's hard to explain in words I guess. Just take a look at the attached file and see if what I did will work. I've worked on homes a lot, and I hate roof plans sometimes. I think what I did will work. There are other way's to do this, but I think this at least maintains that idea you were trying to create.

 

I always try to use a 45 degree angle with my bay windows or nooks. Everything seems to come together a bit cleaner that way.

 

BTW, how's revit working out for you. I've heard some good things about it?

 

Adam

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One of the errors I found was the roof angle that you were using on the roof plan. In order to maintain the same roof pitches, the intersection would be at a 45 degree angle. Your angle was set at 56.32 degress, it appears.

 

 

LOL Whimps way out.

 

And that's NOT an error the slopes being the same pitch do not automatically make it 45 degrees. If you 'choose' to extend the front face of the bay roof up toward the main ridge for effect.....that changes those angles and can Still Be built. Just makes it hard, sometimes very hard to draw right and get it built in the field the correct way.

 

WDA

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I agree that this is probobly a possible structure, but disagree that you can build anything you conceive...

 

pffft...I was a pick up Carpenter before being a building inspector and have seen many buildings that looked just like that before I fixed them ....some of the dang piece workers apparently thought they were M.C. Escher ;)

 

IGD :p

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...BTW, how's revit working out for you. I've heard some good things about it?

Adam

 

Revit is great !!! I can not speak but highly of the technology that drives the app. I will say though anyone looking to implement it is up for a bit of a learning curve but not as steep as other apps out there (adt for example)- the trick is to think outside the autocad mentality when it comes to drafting and understand the relationships of building compoments and its graphic representation within revit. The 3 firms I've implemented so far absolutely love it and are getting up to speed with it. One of them doing most of their work in it already and using ACAD just a viewer almost.

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Only real issue is having adequate bearing and nailing where the common valley and first hip rafters come together at the wall.... LOL RIght Mr Building Inspector? ;)

 

WDA

 

Yes that looks like it might need some extra purlins and kickers at the least ;)

Why you wouldn't just run the main rafters through and tack on the feature is a question of whether you need the head room or not I guess :cool:

 

IGD

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Only real issue is having adequate bearing and nailing where the common valley and first hip rafters come together at the wall.... LOL RIght Mr Building Inspector? ;)

 

WDA

 

Referring to your animation. that is a way overcomplicated to construct that thing.

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The reason I ask is because I can not get the top ridge to be straigh or paralell to the ground when I build it in Revit. It is always slanting towards the font.

so i modeling it in 3dsmax and I just can not understand why I can get it to work. some people sugested that maybe this roof can't be built and therefore it cant be modeled in revit using the roof tool (I dont want to fake with a custom family) so please advice

 

Its your pitch thats the problem... me thinks... You seem to be

allowing the same pitch for all 3 planes... the 2 outer surfaces on plan

will have the same pitch and the inner one different and the length

of you ridge will be determined by this.

 

If you like having a sloped ridge thats not a problem as far as buildability

goes... you roof wont be warped in any way.

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Its your pitch thats the problem... me thinks... You seem to be

allowing the same pitch for all 3 planes... the 2 outer surfaces on plan

will have the same pitch and the inner one different and the length

of you ridge will be determined by this.

 

If you like having a sloped ridge thats not a problem as far as buildability

goes... you roof wont be warped in any way.

 

 

well the sloped ridge is whats killing me ;)

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well the sloped ridge is whats killing me ;)

 

Make the pitch of the middle roof surface higher / steeper... until

your ridge becomes straight... Can you alter different planes in revit?

If not you will have to model all 3 planes as different roofs and adjust

the pitch.. its kinda "suck it'n see stuff" but it'll work for you.

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The problem I have with Faking something is that it cant be built. Which then its no better than 3dsmax. moreover revit is CAD program from which I will be able to get CDs that are accurate. do you know what i mean?

 

This roof can be built no problem ( no faking it)... take a look at any of Frank Gehry's

buildings.... anything can be built within reason... and this simple

roof structure of yours is well within reason... these roofs can be seen

all over the world... its only a alternating simple pitched roof.

 

If you are worried try and build it with foam board... this will help

you understand the geometry also... but trust me... its not one

to get worried over

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