Modelling a roof with a BIM software
How to draw a roof with an architectural BIM design software and how to adapt the pitches?
The great potential and the benefits that derive from the use of BIM software are becoming evermore evident to its users. A 360° solution that addresses design, construction estimating and photo-realistic renders now vitally important for those who constantly pushed towards technological innovation.
The building industry professional can now go in that direction and take advantage of the best BIM software that can simplify the modelling processes behind even the most complex of projects and easily produce the entire set of construction documents together with media illustrations with the use of models to create 3D visuals.
This obviously means that you can create detailed projects in a fraction of the time necessary compared to classic “CAD” based procedures. Just imagine the amount of time saved when the change in a single detail, is automatically re-aligned in all relevant drawings throughout the entire project revision.
In projects where various disciplines are combined, each contribution to the model can be shared, improving design team coordination, reducing conflicts and the need to re-process design ideas and client requirements.
Drawing a roof with a BIM software and assigning the various objects
Let’s have a look at how a typical building’s roof top is modelled using the specific built-in editor, and how to adapt the objects to the pitched slopes using Edificius the architectural BIM design software developed by ACCA software. In this case, we’re talking about using multiple objects because modelling a roof in 3D, means combining different geometrical elements that form the building’s top covering system and in some cases, defining the relating supporting structures too. Edificius is a BIM software that contains a lot of features that are easy to use, but they need to be combined with each other to get the best results.
Edificius makes modelling any type of “Roof” object with its intuitive and functional tools very easy.
The first step is to define the Roof object’s footprint by tracing its perimeter.
- Roof selection and modelling – step 1modelling
- Roof selection and modelling – step 2
- Roof selection and modelling – step 3
- Roof selection and modelling – step 4
The program provides further assistance with various “snap” aids that speed up drawing while maintaining great precision.
- Detail of roof modelling – step 1
- Detail of roof modelling – step 2
- Detail of roof modelling – step 3
Once completed the last segment of the perimeter polyline, we can terminate this first phase with the “Finish” button available in both the local pop-up menu and the program interface’s toolbar.
- Completing the roof modelling process – step 1
- Completing the roof modelling process – step 2
Customizing the roof top design
The Roof Editor is equipped with easy to use but powerful modelling tools that allow even the most inexperienced of designers to completely customize the roof structure.

Auto-pitch button
Even an automation feature can compose a pavillion type roof top at the click of a button. A great advantage that allows the user to avoid all the boring line projections and concentrate on more stimulating creativity aspects.

Roof object Editor menu
Higher levels of customisation can be achieved by entering the “Edit” mode to manually edit each of the roof slope footprints and intersection nodes.

Customising the roof top
Dormer opening can also be added together with sky light openings and eaves. Each of these are easily inserted by selecting them from the roof editor’s object menu.
- Roof pitch selection
- Roof customisation
You can also define the sloping direction and inclination for each of the roof slabs and dynamically adjust how they connect to each other in 3D view.

Adapting the roof pitches
Here we can see how two roof slabs are connected up graphically.

Edificius connecting the roof slabs
Let’s add some extra nodes in the roof design to customize an additional roof element.

Edificius editing roof slabs
Once the roof design is completed, the Roof object’s subLevel is automatically created.

Creating the roof subLevels
The rising walls from beneath are quickly aligned to the roof’s subLevel and the wall’s excess elevation is automatically cut off at the bottom side of the roof slab.
- Selecting Roof objects
- Associating Roof objects
- Roof closed
Click here to download Edificius, the architectural BIM design software