Best way to cut a roof at joins?

Best way to cut a roof at joins?

vanderloo5
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Message 1 of 18

Best way to cut a roof at joins?

vanderloo5
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I remember seeing Paul Aubin do this by making a line at the join and cutting back to the line but these lines are very difficult to select.

Can someone show me a trick for cutting away the unseen part of this little California roof underneath. It needs to be just an overbuild roof.

Thank You

Roof overlay.png

Roof overlay2.png

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Message 2 of 18

jay_colc
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Modify Tab > Roof Join Tool > Click on Roof Edge and Roof Slope

 

jay_colcombe_0-1730808508689.png

jay_colcombe_1-1730808665082.png

 

 

Jay Colcombe

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Message 3 of 18

vanderloo5
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Thanks Jay. That worked on one side but not on the other. I've tried several times and it keeps saying can't join roofs. But I can't see why. (see attachment)

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Message 4 of 18

jay_colc
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I can only think that the Roof of the Left if too low for it to cut but should work, try that Face first this time does that make a difference?

 

Another possible solution is drag the Left Edge of the linking Roof back so it can find a Face to meet against rather than cut back?

jay_colcombe_0-1730822337542.png

 

Finally you could use the Dormer Tool which may be what you originally suggested for the side that will not join automatically

Help | Dormers | Autodesk

 

jay_colcombe_0-1730822243945.png

 

Jay Colcombe

Autodesk Certified Instructor
Revit Architecture & Structure Certified Professional
AutoCAD Certified Professional
B.Sc. Hons Civil & Structural Engineering

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Message 5 of 18

vanderloo5
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Tried em all. Getting different undesired results every time

Message 6 of 18

SteveKStafford
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Use Join Geometry to join the middle roof with the other two roofs. Then in a roof plan or site plan you'll be able to see the valley lines, add a reference plane at each. Then edit the sketch of each roof and modify the sketch so the boundary follows the valley edge. If the eave does not leave an edge that can be slope defining. You can create two roofs that have their slope defining edge at the ridge instead, using a negative pitch. This way the "cricket" roof between the other two can end in a "point". If you post a version of the file with just the roofs I can modify it to show you what I'm describing.

 

SteveKStafford_0-1730840893002.png

SteveKStafford_1-1730840927697.png

 

 


Steve Stafford
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Message 7 of 18

vanderloo5
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I see that somehow, in the course of my 100 attempts, the roof shrank. It should go all the way to the outside on both ends.

With that said though, I think the problem is that these two roofs are separate roofs, (see attachment),

Roof overlay5.png

and I can't get join geometry to work to bind them together. If I could, this operation would probably work.

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Message 8 of 18

SteveKStafford
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Copy the roofs to a blank file and upload it here?


Steve Stafford
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Message 9 of 18

vanderloo5
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Here it is Steve.

Thank You

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Message 10 of 18

vanderloo5
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Message 11 of 18

azad.Nanva
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You can always use the mass:

 

(view in My Videos)

 

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Message 12 of 18

azad.Nanva
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and you can spend more time and make the clean one:

 

(view in My Videos)

 

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Message 13 of 18

SteveKStafford
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Accepted solution

Here's your file after I tweaked the roofs. I used Join Geometry on each roof so the valley line remains visible while editing the roof. Have a look. There is some subtle alignment issues between them that I didn't dig into but the general concept is there.


Steve Stafford
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Message 14 of 18

vanderloo5
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Thank You Steve. Wondering where you see the subtle alignment issues?

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Message 15 of 18

SteveKStafford
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Where the three roofs meet at the bottom of the valleys and where the two parallel roofs meet each other at their valley. It's tiny, you have to zoom in to see it.

 

SteveKStafford_0-1730921355514.png

 


Steve Stafford
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Message 16 of 18

vanderloo5
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Any idea why the 2 roofs wouldn't join geometry? I think I never would have had this issue if I could have gotten them to join.

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Message 17 of 18

SteveKStafford
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All the roofs I need to use Join Geometry on did so without issue. I don't know why they didn't for you but I didn't have any walls in the model to interact with the roofs. It's possible that a wall that is attached to one or more of the roofs was interfering because of its own relationship to the roof(s).


Steve Stafford
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Message 18 of 18

ToanDN
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You cannot join the roof on both sides because the two joints overlap each others.  You can only do it if the two cutting roofs are farther apart than what you have.  You could simply join one side then use a void extrusion or a solid mass to cut off the roof.  Also, don't you want to remove the part of the main roofs below the gable roof to create an interior space there?

 

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