Modelling a roof top with BIM: the Daegu Gosan Library project

How to Create and Model a pitched roof top with an architectural BIM design software: a step by step video illustrating the DAEGU GOSAN PUBLIC LIBRARY remodelled with Edificius

Modelling a sloped roof top with all of its tricky slab elements, is certainly one of the most fundamental and delicate phases in designing a structure. Things may start to get easier when combining a BIM software for architectural design, integrated with a real-time rendering engine. With this powerful design control tool, the designer can continuously view and control the design process in an extremely realistic manner.

To understand how to model a complex roof top in detail, we'll quickly cover all the various modelling steps necessary to re-model the Daegu Gosan Public Library. This particular design was conceived by the US architecture design firm, MARTIN FENLON ARCHITECTURE that participated in the international competition that was organised for the building of an intriguing bookstore in the city of Daegu, in South Korea.

Render of the Daegu Gosan Public Library modelled with Edificius

In the detail videos, we can see how to create a complex roof top made up of multiple pitched slabs. Even the glazing elements on the roof top have been modelled and equipped with metal profiles which have both a support function and a sun protection function.

Modelling the building's roof top structure with a BIM software

00:00 min – We'll start off by importing a drawing of the roof footprint in .dwg format. The import feature "DXF/DWG CAD drawing" allows us to do this and is available in the "2D Graphics" menu.
00:30 min – Selecting the "ROOF" slab object in the ARCHITECTURAL Objects menu, we'll simply trace around the perimeter of the roof
00:57 min – At this point, the roof editor opens for further editing.
02:40 min – Each section of the pitched slabs are quickly adjusted in terms of inclination using the three-point mode. For each of the slabs, we'll place each of the three nodes on the slab vertices and then in 3D view graphically adjust their elevation.

Connecting the building envelopes

00:00 min – Once the editing phase is completed, we can now concentrate on connecting the building envelopes to the roof object. We'll select the building envelopes and in the properties toolbox, assign its "Height Reference System" by choosing the roof as the upper sub-level. You'll notice how all of the selected walls are automatically adapted to the ceiling side of the roof structure.

Modelling an opening in the roof object

00:00 min – To define the edge beam that delimits the roof opening, we can see that even flexible modelling objects, such as the "Landscaping Wall" can be disconnected from the terrain level and used for solving complex modelling issues on the roof. In the properties toolbox we'll set its depth to zero and a height at 0.4 m

Creating a stained glass section in the roof object

00:03 min – To insert metallic profiles, we'll use the Magnetic Grid object for extra modelling precision.
01:40 min – By selecting the "Steel Beam” object, we'll then choose one of the many profiles, available in the program's Library and then activate automatic generation. With the Magic Wand tool, we can easily place our beam objects over the selected segments of the 3DMG automatically.

00:00 min – Here we'll proceed with building up the magnetic grids to create our snap nodes. These will then serve for tracing the metallic elements that will serve as a supporting structure for the sunscreens.
04:40 min – Selecting the "Solid Extrusion” object, we can then choose the appropriate profile. An 80x300 mm profile type. We'll then proceed to tracing our solid extrusion using the snap aids and setting up the correct alignment axis.

00:00 min – The glazed panel is represented in terms of a precise modelling process using the “PANNEL” object and by choosing the “Metal-Glass” panel type from the catalogue. A first insertion point sets its height and using the object grip, we can also rotate it accordingto the desired direction.

Creating the working drawings with Edificius

00:00 min – Done by adding a “Floor Plan” object and inserting it at the roof level.
00:08 min – Same with the cross section. Simply add the object and trace a cross section line. Again, this object is inserted at Roof level and a cross section drawing type is automatically added under the corresponding category node
00:50 min - Now by simply drag and dropping the individual drawings (floor plans and cross-sections) from the projec navigator nodes to our sheet layout (A0, A1, etc), we can easily build up a first example of our Working Drawings.

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