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Angled Roof - How do I construct a skillion roof w/ 2 angles

Anonymous
Not applicable
With the roof tool how do I construct a skillion roof with two angles/pitches.

For example.
Select the roof tool,
Selected the simple skillion roof,
enter the first node of the roof pivot line,
then the second node (usually vertical or horizontal)
draw a simple square roof with a 6 degree pitch.

Now this is where it gets tricky.
If I move the roof pivot line to an angle I get a roof with two angles.

What I would like to know is how to work out where or what angle to place the roof pivot line to get a main roof pitch at 6 degrees and be at 10 degrees (in its side elevation)

Is there any geometry or simple way of working this out.

Thanks in advance.

Brendon
25 REPLIES 25
Thomas Holm
Booster
I'm not sure exactly what you mean. The pivot line is by definition horizontal, and the slope angle is defined perpendicular to the pivot line. Neither of the "two angles" you mention is the true slope angle.

But to approach this in a less theoretical way, I'd simply construct this by making one test roof 6° like you said, another with slope angle 10° and pivot line perpendicular to the section cut direction and then intersect them. Then make a section in the intersection, measure the angle and make your final roof with that slope, perpendicular to that section.

I'm sure there are other and maybe better ways.
AC4.1-AC26SWE; MacOS13.5.1; MP5,1+MBP16,1
Barry Kelly
Moderator
There was a soulution to this (or something very similar) in this forum some time ago.
The problem is coming up with the appropriate key words to do a search that will get a result - not jus a thousand posts about roof pitches.

Thomas' method should work but another would be to work it out mathematically or graphically.
At a certain length along the 6° pitch (say one metre) determine the height or rise of the roof.
How far along the 10° pitch would you have to go to get to the same height.
The pitching line will then run parallel to these two points.

I'm sure there is an easier way like stretching in 3D or finding that other post.

Barry.
One of the forum moderators.
Versions 6.5 to 27
Dell XPS- i7-6700 @ 3.4Ghz, 16GB ram, GeForce GTX 960 (2GB), Windows 10
Lenovo Thinkpad - i7-1270P 2.20 GHz, 32GB RAM, Nvidia T550, Windows 11
Anonymous
Not applicable
I would start with two (temporary) connecting roofs with the correct slope angle. Then stretching graphically (=trial and error) in the 3D window to achieve the best possible result. I still have not found another way of doing this...
Thomas Holm
Booster
Joeri wrote:
I would start with two (temporary) connecting roofs with the correct slope angle. Then stretching graphically (=trial and error) in the 3D window to achieve the best possible result. I still have not found another way of doing this...
I think my way is faster
AC4.1-AC26SWE; MacOS13.5.1; MP5,1+MBP16,1
Anonymous
Not applicable
The method Barry may be referring to is one Link explained
in a thread that I can't find but I copied his post and diagram.
See attached
Peter Devlin
Anonymous
Not applicable
Use Meshtool
Djordje
Ace
If you know three points of that roof, and you do, define them in 3D (place anything that you can snap to in 3D window), open 3D window, do the roof plane throught those three points, shape to taste.
Djordje



ArchiCAD since 4.55 ... 1995
HP Omen
Barry Kelly
Moderator
Djordje wrote:
If you know three points of that roof, and you do, define them in 3D (place anything that you can snap to in 3D window), open 3D window, do the roof plane throught those three points, shape to taste.
There - I knew there was an easy way - thanks Djordje.
I've never had the need to define a roof in 3D though but it works really well.
As Djordje says the trick is to define the three known heights in 3D so you can snap to them.

Barry.
One of the forum moderators.
Versions 6.5 to 27
Dell XPS- i7-6700 @ 3.4Ghz, 16GB ram, GeForce GTX 960 (2GB), Windows 10
Lenovo Thinkpad - i7-1270P 2.20 GHz, 32GB RAM, Nvidia T550, Windows 11
Anonymous
Not applicable
Ok,
following are a couple of snap shots of what I'm after.

The first is showing with two roof in plan what I trying to do with one roof and not using the mesh tool.

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