Fixing hip roof corners

[DenisUser]

Hey,

Probably a simple question, but I haven't found yet some place that shows how to do that.

Is there a better way to do a hip roof with the same eaves length, but different slopes?

If I put two parts of the roof at a different slope Archicad wants to displace the diagonal ridge at the eaves corner. Instead, it should displace the diagonal ridge so that it misses the corner of the wall but still goes into the corner of the eaves. I cannot find a way to move this ridge in the way I want it to move and automatically Archicad does what you see in the picture. Is this done only manually with single-roof planes?

 

[Lingwisyer]

Your red line is actually moving the pitching point on your steeper sloped section. This would equate into placing spacers under your rafters for those sides? The hip will rotate clockwise as you increase the pitch of the left roof. This is a mathematical fact given fixed pitching points. The only way to have the hip meet the corner is to shorten your eave lengths. To emulate the spaces mentioned before, and keep your "eave" lengths, you would just need to extend your pitching line outside your wall line.

Ling.

[DenisUser]

No this is not exactly correct that the only way is to shorten eaves. I have been doing structural design for the manufacturing of roofs for about 5 years (mostly trusses). This is a simple situation. You can have different slopes and ridges go directly in the eaves while both eaves are the same length. I am gonna put an example pictures with this post. It is not the same roof, but visually I need the same result. This ridge should move further away from the wall corner.

[Barry Kelly]

It can be done with the same eaves, but as Ling said, the pitching position or height needs to be altered

In your image you can see the pitching height is different.

Barry.

[mthd · Accepted solution]

Hi @DenisUser, I would split the roof into separate planes and edit each one from there. Like you I started with truss design (In the mid 80’s for me). We have probably drawn thousands of roofs like @Barry Kelly and @Lingwisyer have also done. You will figure it out in the 3D view.

Edit. The hip is not at 45 degrees as depicted on your truss plan. Measure that angle and adjust your hips accordingly. Hopefully that will work ?

In the end if we draw the roof shape and the truss designer will follow our design. If you have to follow the truss layout first because the trusses are already made then adjust accordingly.

All good !

[DenisUser]

Ok. Thanks, Barry and mthd. I understand that pitching height is different. Was just asking if Archicad can construct this kind of surface with more automatic tools. But I guess I have to do it separately then. Was working with Roofcon/trusscon and then Mitek Pamir. Those were very nice for designing roof surfaces and timber structures 😄 

[mthd]

I started with Bostich but it was only 2D and in the old DOS system too. Yeah it would be nice if AC could edit it as one entity but it has its limits as to what we can do with it. You would have to go back and view the official roof editing video series, many versions ago but they are available on YT if your search for them.

No worries !

Link: This may help you from 2011.

https://www.youtube.com/watch?v=CSNyWR57Ylk

[Lingwisyer · Accepted solution]

Shortening the Eaves was in relation to using a Multiplane Roof with "Eaves".

Given your second image, I would not even use the Eave setting. Since you are resting the bottom of a truss on the wall rather than the rafter itself, I would set the Eaves to ZERO and just offset the whole Reference Line from the wall line. In that way you can set your pitches to what ever you want, your hips and ridges will automatically adjust and your eave height will stay consistent; your story height, plus maybe your fascia height.

Using Single Plane Roofs with an "Eave" as suggested by mthd means that you need to work out the pitching height of each roof... which you would probably do in 3D. The intersection can be done automatically by just intesecting the roofs. In the end, I feel like you do not save youself any effort using Single Planes and juat have to do more things in 3D.

Ling.

[mthd]

Hi @Lingwisyer, it’s hard to tell without seeing the whole roof plan that is covered by that roof part in question. There are always more than a few solutions to get that roof to work correctly. Ideally you want the hips to stop right at the corners like the truss layout does. Because there is not enough information, I suggested that they could if needed, right click and split into separate roof planes.

Just looking at the truss layout, you would be able to drag the ridge point that meets the hips out till the angle is the same as the one on the truss layout. In this case you probably wouldn’t need to split into separate planes depending on what is happening at the other hip end ridge joint. 

By fiddling around in 3D with each roof plane you learn how to pitch your roofs correctly and what each one needs to do to all line up correctly. Especially when it’s preset by a renovation or addition.

[Lingwisyer]

you would be able to drag the ridge point that meets the hips out till the angle is the same as the one on the truss layout

This would change the pitch of the relevant face?