Draw roofs
Create roof rooms with roof type, roof height or roof pitch, knee wall and rotatable roof orientation
Overview
The roof wizard creates a complete roof room from a horizontal floor-plan polygon: a floor surface, sloped roof surfaces and — depending on the roof shape — vertical wall surfaces (gables, knee walls). The result is a regular room in the chosen storey, whose surfaces are already assigned constructions and boundary conditions.
Invoking
In 
Add mode, “Add geometry” panel, Zone group: button 
Roof. You then draw the roof floor plan as described in Draw rooms (vertex list, building/storey selection, elevation checkbox) and finish with Create polygon.
If the drawn floor plan is not a rectangle, the program preselects the Complex roof shape roof type.
”Roof properties” page
Roof type
The Roof type: combo box offers:
| Roof type | Description |
|---|---|
| Shed roof | one sloped roof surface |
| Gable roof | two sloped roof surfaces with a ridge, gable walls at the end faces |
| Mansard roof | doubly kinked roof surfaces; the kink position is fixed (10 % of the long side, 50 % of the ridge height) |
| Hip roof | four sloped roof surfaces |
| Complex roof shape | arbitrary (including non-rectangular) floor plans; the roof surfaces are generated from the full polygon via a straight-skeleton algorithm (this also covers, e.g., the tent roof) |
For the four named roof types only the first four floor-plan points are used; with Complex roof shape all points are included.
Roof height or roof pitch
Two radio buttons determine which quantity you specify — the other results from the geometry:
- Roof height: — height of the ridge above the knee wall in m (default 2 m). If the storey has a height assigned, it is adopted.
- Roof pitch: — pitch angle in degrees (default 45°).
The roof preview in the scene updates with every input.
Knee wall
The Knee wall: checkbox activates a continuous vertical knee wall below the roof surfaces; you enter the height in the adjacent field (default 0.6 m).
Rotate roof orientation
Rotate roof orientation cyclically shifts the assignment of eaves and ridge around the four floor-plan points — this lets you, for example, reorient the shed-roof surface or the gable ridge without redrawing. For the Complex roof shape roof type the button is hidden, since there the entire polygon is processed by the algorithm and a rotation would have no effect.
Constructions
In the collapsible Show constructions area you select Roof construction:, Wall construction: and Floor construction:; the preselection and behavior match the room page (project default constructions, highlighted matching entries).
Create roof
Create roof creates the roof room in the chosen storey:
- The floor surface gets the name “Floor”, the floor construction, and the interior/ground boundary conditions.
- Roof surfaces (“Roof surface 1”, “Roof surface 2”, …) are colored reddish-brown and get the roof construction, wall/gable surfaces (“Wall surface 1”, …) get the wall construction; both with interior/exterior boundary conditions from the project defaults.
- The floor-plan base area is stored as the room parameter “Area”, and the room volume is computed.
Good to know:
Create a dedicated storey for the attic in the storey management and draw the roof floor plan with the “Set polygon points to elevation level” checkbox enabled — then the roof room sits exactly on the top edge of the topmost full storey’s ceiling, and the later component connection reliably finds the shared surface between the ceiling and the attic floor.