The Roof Modification Options dialog box allows you to Define Vertical Plane Ends (Gables), Change Eave-Gable Overhang, or Define Barge Lines in the same step as constructing the 3D model. This can save time, and in many instances, the correct model geometry can only be achieved if you select the appropriate option at this stage.
The gable roof on the left can only be constructed if the wall lines are selected as Vertical Planes (gable ends) at this stage of the process.
⚠️ Important: The options must be selected in order, as numbered in the dialog box. If you select barge lines then go to vertical planes, the barge lines option is cancelled.
🔧 1. Vertical Planes (Gables)
You select 1. – Define Vertical Planes if you need to have the software create a gable end instead of a hip end. Select one or more wall lines where you want a gable or vertical plane to be built. This may also result in what some roofers call mono-ridge.
Click the wall lines where you want gables
Right-click to finish selecting gable wall lines
Click [Yes] to confirm the wall lines adjacent to the gables or mono-ridges
While nothing happens immediately, the software is now ready to make the selected eave lines into gable ends during construction of the roof.
A variation on using the Vertical-Planes option on the bottom wall line.
In Plan view:
In ISO View:
A regualr gable end above the entry awning:
💡 Note on Barge/Rake flashing on Gable Ends
Barge/Rake lines are drawn as sloping lines after you have modified the outline to tell the software that these lines are "barges" (refer below) or you select the eave line to be a vertical plane (gable) using the command described here. As a result, when the lines are drawn and the model is created, the lines become "GABLE" lines.
Other line-types that might be used on a 'gable end' are FASCIA-BARGE, FASCIA-ONLY and BARGE-ONLY, but the operator must manually select each line to change it to one of these options.
Any fascia flashing defined as part of a job is applied to an eave line (FASCIA) as FASCIA, but to a GABLE line as FASCIA-BARGE. While it may be the same flashing/trim product, but it appears as a different item in the flashing cutting list due to the possibility that while the same shape, it might be fabricated to be different girth to account for the geometry of the slope.
FASCIA-BARGE in most instances just highlights that it's a fascia flashing, being applied to a barge or gable end. This becomes an important distinction if you have defined accessory items such as 'barge-mitres' 'rake-corners' etc that are only applied if the fascia line slopes up or down.
🔧 2. Change Overhangs
To alter the eave or gable overhang for a specific wall, click on
[2. – Change Eave/Gable Overhangs]:
Select a wall line
Enter a new eave overhang value into the dialog box
Repeat for additional walls as needed
Right-click to finish changing overhangs from the wall line to the eave
You can enter any value – it is the distance measured off the wall line. The dialog box is displayed after each line is changed.
🔧 3. Barge/Rake Lines
This picture shows an example of barge/rake lines on a roof – where the eave height of the roof changes up and then down again. In this case the barge/rake lines are extended under the eave (Mod-Roof > Extend Barge).
Select [3. – Define Barge Lines]
Select the lines that are required to be barge or rake lines
Right-click when you are finished selecting lines
A barge/rake line will be required where the eave height changes as shown in the picture above.
⚠️ Important Notes about Barge Lines
Barge lines define a change in eave height in a single roof plane. To make geometric sense, there cannot be a single barge line, but a combination of barge lines which collectively compensate for a change in eave height. In simple terms, if a barge line goes up an amount, it must come down the same amount or an eave line will end up sloping, which you cannot have.
🛠 Completing the Process
After you have finished selecting vertical plane lines, new eave offsets and barge lines, click [Continue] and the roof is drawn showing all the eaves, hips, ridges, valleys and barges. On each roof outline, a plane is created. This simply links its lines together to form a single roof plane. It is this plane which is used to calculate the area of the roof as well as other roof geometric properties.
Visualising Roof Planes
To visualise the plane, you can select Tools > Show-Planes which draws each roof plane with a hatch or filled planes as determined by your preference settings:
Hatch lines normal to the eave indicate metal roofing
Hatch lines parallel to the eave indicate tile or shingle roofing
Diagonal lines indicate a low slope material such as BUR or single ply
To turn off the hatching, select Tools > Hide-Planes. When the roof plane is drawn without a hatch, a small tick mark is drawn in one of the corners of the plane. You would then select this tick mark if you want to select that roof plane for any reason. Because the little tick mark is very adept at hiding itself, you should turn your roof planes ON any time you wish to modify or select roof planes as part of the modelling process.
⚠️ Note: Because a roof plane is controlled by the bounding lines (the eave, hip, valley and ridge lines for example) you cannot delete a roofline without first deleting the roof plane the line it is attached to. Also note that most roof lines may be attached to at least 2 roof planes.