Roof of irregular plan

array81

I have a floor plan of an attic very irregular:

I have spend many time to draw the roof and the result is not a good result:

What is the best way to draw a roof like this (irregular plan)?
Are there some plugins that can help me?

pilou

FormZfree has a cool one!
Import SKP export STL so Didier Bur can help you!
Import/ export STL

Else Tig has a good one!

pbacot

Consider how the roof will be built. What is wrong with what you got? Plugins don't know what to do with unusual structures.

S Shepherd

For starters, Each facet should be flat. I'd try to eliminate those diagonal hidden lines.
If the overhang could vary along the walls, you'd be able to keep at least the long eave straight, simplifying that side of the roof.
Of course, this is all guesswork without the model.

Shep

TIG

You are running into the limitations of real-world geometry.

If a roof's eaves is horizontal and its related ridge is not parallel to that eaves, then that ridge cannot be horizontal, at least if it is to bound a single roof plane - that ridge must slope.
Conversely the same applies to a ridge and a sloping eaves...

If both the eaves and non-parallel ridge must be made horizontal, then there are really two possibilities...
Either there is an extra 'flat' piece of roof as a non-rectangular shaped 'ridge-capping' to disguise the anomaly, or the roof form itself is somehow 'twisted' - that is, the roof surface consists of two or more 'facets' to form a shallow curving form - in reality if this twisting is slight, then this is disguised by the angles and spacing of the slates or tiles covering the roof, if it's more pronounced it is betrayed by the slates' coursing running out near the ridge, or perhaps appearing uneven in the main body of the roof's surface. If the roof is say thatched then these anomalies are masked very easily.

If this existing building has non-parallel walls then check for which of these is the likely 'culprit'.
You cannot expect SketchUp to model something that's impossible in reality - just make the best approximation...

nlipovac

You should build roof sides so they are parallel like in square floor plan. Than use your floor plan to determine where walls cuts roof and then use protractor to mark where roof should extend fromthe walls of your floor plan. And then you cut your roof to size you need.

sonder

Like TIG says. If your goal is to have a level ridge, then your eave will be sloped. If your goal is to have a level eave, then your ridge will be sloped. If your goal is to have a level ridge and eave, your walls need to straighten or you need to frame it in a parabolic which is what you got in your result, which is very expensive and difficult to frame.

ccaponigro

You could just do a level return and allow the overhang to vary.

TIG

It's clear from the various posts that you have many options when adding a roof over these walls.
The last poster's suggestion is to ignore the masonry walls and make an orthogonal roof over them with parallel eaves and ridges, but with varying soffit dimensions.
If this is acceptable to you then you might have as a simple roof structure and finish as you could.

Otherwise if you must have parallel eaves and ridges you must either accept a roof surface that is not in one simple plane, with twisted facets are needed to achieve the form, or a piece of 'flat' roof at the ridge to fill in the inevitable gap between the two single-plane roofs that meet there.
In these cases you need to consider the complexity of making the non-conventional roof structure and its finishes.

If parallel eaves and ridges are not a must, but single plane roof for each section are still preferable, then you need to decide it you are to slope the various ridges or the various eaves. The former is probably the more conventional structurally - it's effectively a very shallow hip construction with the normally horizontal ridge-board becoming in effect a sloping hip-tree - the roofing material is easily trimmed and covered by the ridge capping: otherwise sloping the eaves means non-conventional sloping wall-plates, odd-walling etc, and probably ugly weirdness at the lower edges of the roof, where material at the eaves would need cutting and finishing oddly - somewhat like a shallow valley gutter...