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simple roof help

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It seems I can't reproduce this very common roof structure and ask for your help.  In the attached image, I want to make the plane of roof A be co-planar with roof surface B, as well as have that roof portion overhang a bit as shown.  I understand it means that the bearing height of the wall shown with the purple line must be lower than the bearing height of the wall with the yellow line.  However, when I try to reduce the bearing height of the purple wall, it will not allow me to fully lower it so that the planes are co-planar.  It does allow me to lower the plane of roof A, but not enough to make it co-planar before I get an error message.


I know that I can change the roof into generic solids and then make the change, but I don't want to do that, since I can't return it to being a roof object.


Any help is appreciated .....   thanks   

roof test.jpg

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I don't think you can do it and have roof planes A & B perfectly flush using the Roof tool. If getting it almost perfect is good enough then you can do it either by:

  • Lowering the bearing height of wall A 99.999% of what it would need to be to make the roof planes flush or
  • using the roof overhang facility. I.e. move wall A 99.999% flush with wall B and then increase roof A overhang as required.

Both ways will still leave a line between roofs A&B in hidden line and OpenGL with edges on. No line with OpenGL without edges however.


These two roofs below were done using the methods above.


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Boh:  thanks for the reply.  I needed someone with real skill to verify that it isn't possible.   I suppose sometimes the 99% technique might be OK, but I want to render it in OpenGL without seeing the line.  Also, in RW the shingles don't line up.   I found a not-too-complicated work around .     


It is a bit frustrating though  .....  this roof shape is very common in my area for old ranch houses that are now being renovated.  The roof tool let me down.

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Boh has the geometry basically correct.  To fix this:


If your roof planes are not already separate objects, ungroup the roof object so that it is a set of roof planes.  Then make a polygon that outlines the edges of your roof A, bearing in mind that it will extend beyond the eave of roof B as Boh illustrates.  Then double-click on B, paste-in-place your polygon and add the two.  Then, after exiting the roof plane edit space, join all your roof planes using the "Join" command.


The roof tool isn't designed to automatically generate a roof of this shape.  If you start with a polygon, it will assume that you want all your fascias to be at the same height, and will add a valley and extra plane at the intersection of A and B.  You have to go through the plane editing process every time you want to create a roof like this.  I always start with a simple rectangle, get a hip roof, ungroup, and edit the planes.  If you do it that way, you won't usually have to join planes, they will already be aligned correctly.

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15 hours ago, P Retondo said:

Then, after exiting the roof plane edit space, join all your roof planes using the "Join" command.

I tried this @P Retondo and using the Join command on the roof planes doesn't seem to do anything. Is it supposed to turn the roof plane objects into a roof object?

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Starting with this roof:



Ungroup, draw a polygon in plan that encompases A and C up to the hip of B.  Get rid of A and C and edit B to incorporate that polygon.  Then you end up with this:



Faces B and D do not join at a hip.  To fix this, join D to B using the same "Join" tool used to join two lines



Click D, click B, and get this:


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