I need help with complex roof modeling. At least this looks complex to me as an interior designer. I’m having a difficult time understanding the small bits in the front. Would love suggestions on resources that explain the components of residential roofing and how to model them. TIA!
It’s difficult to know exactly how that roof works without also seeing a plan. Also, I am not clear what you mean by “the small bits”. Perhaps you mean the eaves returns on what looks like a kind of broken pediment.
Roofs of this traditional kind are usually pretty easy to model, especially when gable ended like this.
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Roof plan is attached for
reference. I guess I’m just not entirely sure where to start. Is that what those small roof pieces are at the eaves? How would I find the pitches of these pieces?
The image in your original post looks a lot like a Sketchup drawing. I presume you don’t have the .skp file?
I think what you have going on there is the main roof being extended down a small way below the default eaves line and then wrapped around the and of the eaves. But that doesn’t look quite right for some of the elevation so it’s hard to know.
As for the pitch angle, if you have a 2D elevation, that should tell you.
I just modelled the front corner at an arbitrary pitch:
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I don’t have the Sketchup file (yet, will hopefully be getting it) and do have an exterior elevation.
What tools in Sketchup did you use to do this model? You made quick work out of what is taking me a while to understand! I appreciate your help.
It looks like that is a “shingled eave return” at the end of the gable with a 6" rake fascia and a 6" return eave fascia, I just don’t know how to get the darn thing modeled.
I can tell you how I did it.
I started by drawing the gable end of the main roof. Then Push/Pulled it to its required length.
I did the same for the two projecting gables.
I then modelled a 2D section of the eaves outshot (basically a vertical triangle). That had the same pitch as the other roof sections.
Then I traced a line that described the extent of outshot and used that as a path to extrude the triangle. Then I tidied up any excess lines.
To make it look realistic, you would have to add the fascia depths and overhangs. All easy enough.
If you do get the SU file, do you need to model anything? Lokks liek it’s been done for you.
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As Simon pointed out, if you will be receiving the SU model, what exact information about the roof construction will be required? It will be included in the SU model, for your inspection.
If you are rebuilding the roof structure, there are extensions that will assist in the design process. One example is the Medeek Truss Extension that created this example:
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The model in the picture uses two different approaches. In the ones at the garage the gable “barge” rafter or fascia (sloping white painted piece) is stepped back from the edge of the roof and the roof at the lower end wraps around just like a regular hip roof–but soon returns to the wall with another hip. In the other instance the barge rafter is combined with a horizontal fascia, flush, to form a triangle. A portion of sloping roof is added from the horizontal fascia to the gable wall. This is cut out in the center (didn’t see that at first) and a hip returns to the wall. Can’t model it now, and I assume it will be modeled by someone by the time I return.
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I hadn’t even noticed that there were two different conditions - thank you for pointing that out!!!
Maybe this model will help give an idea (of my interpretation of the plan anyway) and you can see a way to model this yourself. I am sorry I find that it’s hard to translate all the tricks I’ve learned, and my experience with roofs, to some sort of method. I’d have to be able to show you as I go along. This IS a complex roof–not necessarily nice.
I started establishing the basic roof shapes, then I added the dropped eave portions I decided that they were a foot offset in plan and drew them off the main roof plane. Using a standard distance is realistic but also makes it easier to work all the dropped eaves together. Same with the locations where the little hips “cut-back” to the wall. I chose 32" from where the gable “barge” rafter intersects the hip–same in most cases.
I use inferences a lot. Drawing from roof planes and edges that I’ve already made. Once i have some hips created, I infer the angle for the next one etc. It works if you keep it clean and accurate. I use intersect faces after extending faces where they run into other elements. Then it’s a matter of learning where you have to clean up the excess as you go. I use ThomThom’s “CleanUp” to help sometimes.
Cheating?: I used Mirror.rb sometimes, and Extrude tools (to bring the level fascias down. But that can all be done with native tools too.
I use one approach to the hip returns. This is just a study on the roof shapes and doesn’t address actual member sizes or finer details.
roof.skp (135.7 KB)
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Oh my gosh, this is so incredibly helpful!!! I’m going to go over all of this in more detail tonight but your description and model look spot on. I sincerely appreciate your help.
Also, I appreciate the reassurance that this roof is a bit complicated 
Sorry, I missed a detail and didn’t do the gable in the rear correctly. This adds another complexity. To do that gable there is NO hip in that rear left corner (and it’s shown no hip on the plan)-- and this is true on the other side gables. Logically this means that the soffits are all sloped or open rafter tails-- you wouldn’t want to transition to flat eave soffit. Fixing this “manually” is lot of steps, and using follow-me for these hip returns might have been effective in the first place. I also adjusted the walls–that were just eyeballed anyway–to fit the roof better at these sloped soffits. Reminder that this is just a eyeball sketch, not scaled to your actual house plan.
roof.skp (133.9 KB)
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