Mysterious roof bay

[David]

I created this roof by first sketching the long common walls without any bays. When I first attempted to create the bays, either by picking walls, or drawing lines, I got the dreaded "cannot create footprint roof". How very helpful.
Next I created a roof with no zags around the bays, and then split the common define slope line and added the first bay. Worked fine. When I repeated the process for the 2nd deeper bay, I again got the dreaded "cannot create footprint roof". I have been through this many times and cannot understand what is wrong. The attached images are before and during the 2nd bay sketch.

Help Please

[beegee]

Looking at your images and the method you propose, I can see no reason why the roof wouldn't work. The bays are a continuation of the existing roof pitch - right ? The 3 lines defining the bays are all non slope defining - correct ?

Can you post the file ( stripped down as necessary ) so one of us can take a closer look ?

[David]

I have attached a pared file of the unresponsive roof for your kind review. Could not solve this yet, and would be most appreciative of the detective work.

1. The bays are a continuation of the existing roof pitch.
2. The 3 lines defining the bays are all non-sloping.

[beegee]

I think the problem is being caused by the Revit's attempt to interpret the roof footprint geometry. With so many cut angles, Revit thinks that the roof should be broken up if the eaves overhang for the second bump out is anything less than 3'0". See attached image, for what Revit tries to do with that footprint.
You can make the roof work with a 3'0' overhang as per the attached file. You should also be able to construct a small separate roof piece for the second bump out, with a 2'0" eaves overhang and join it to the main roof using Join Geometry.

[David]

Beegee,

I like your first answer best, to wit: "I can see no reason why..." After looking at your file,
I made the roof with 3' overhangs.
Then I reduced the overhangs to 2' 11",
Then I reduced the overhangs to 2' 10",
Then I reduced the overhangs to 2' 9",
Then I reduced the overhangs to 2' 8", I felt like a horse whisperer, coaxing a stallion into harness. but still the overhang would go no less than 2'6 on 1 side. This ain't right. I need to do some more work on this. or I will have to do a 2-d drawing. Thanks again. ... ...Any ideas?

[beegee]

Here ya go.

I deleted the roof portion from the ridge back. Set the bump-out overhangs to 2'0". Drew a new roof for the part previously deleted, then joined the geometry.

Doing it this way, Revit knew exactly what was required of each roof without the confusion inherent when the bump out geometry seems to interact with the other roof geometry.

[David]

Beegee

Thanks for staying with this. I guess what I have learned from this as a general principle, is that a portion of a footprint roof which does not respond as expected, needs to be isolated so that it can be given tighter, more specific parameters. Something like "cannot make footprint roof BECAUSE, highlighted lines are clueless"