Hip Roof adjust ridge length problems

[Rene Pahlavan]

I have struggled with this problem many times and cannot find a ready solution. The problem is that the ridge needs to be a certain length to accommodate dormers. Drawing the multi-plane roof with a set over hang (in this case 4 feet) results in a ridge that is too short. I can manipulate the ridge-line to be long enough, but then the corners get messed up. Splitting into single plane and endlessly trying to properly line up the corners and ridges has proven to be very very difficult, if not impossible. Any suggestions as to how to achieve this? It can't be this hard.
Screenshots attached. One is the roof as built with the orange guidelines that show how long the ridge needs to be. When I stretch the ridge to the required length, the corners go off (2D and 3D view) and droop down (note, the roof area is unchanged). I need to keep the overhang the same length, and do not know how to achieve this.

[Lingwisyer]

You cannot create dormers as part of a multi-plane*.

Rene wrote:
Splitting into single plane and endlessly trying to properly line up the corners and ridges has proven to be very very difficult, if not impossible.

Add a few more guidelines for all the existing hips as well as the dormer offset and it is pretty easy to adjust the single-planes to fit.




Ling.

[Barry Kelly]

Adjusting the ridge length will adjust the pitch of the top and bottom roof planes - effectively moving the roof edge as the eaves depth changes to suit the new pitch.
Rather than then stretching the roof edge out (this will keep the same pitch and adjust the height of the eave causing the 'droop', you need to move the pitching line of the roof.

However, this will also adjust the length of the ridge as you are moving the entire end roof plane - you will be in a 'catch-22' situation.
Adjusting the ridge length will adjust the roof plan pitch and then moving the roof plane to the correct position will adjust the ridge length, so it will no longer be the length you want.

So you may need to do a little planning (drawing lines in elevation) to work out the required pitches you need to set the end roof planes too.
Then just move the roof plane (pivot line) to the required position and you should have the ridge length you want.


Barry.

[Barry Kelly]

I was thinking that you wanted the dormers at the side roof planes for some reason.

To add them to the ends, add extra nodes to the single planes as Ling has suggested.

Otherwise you can add multiple levels to a multi-plane roof and then make the ends of the top level into a gable (dormer).


Personally I like to use single roof planes for anything out of the ordinary.
Maybe because I am 'old-school' from before we had multi-plane roofs.


Barry.

[Lingwisyer]

I have had issues in the past with parts of multiplane roofs disappearing. There is also the issue that the dormer length here is controlled by the elevation of it so some trigonometry maybe require to achieve the desired size.



Ling.