Designing the Viipuri library with a BIM software
Let's find out how Alvar Aalto would have designed his famous Viipuri Library with the help of a modern BIM Oriented software
The Viipuri library is an internationally acclaimed design, built in 1927 by Finnish architect Alvar Aalto. Considered a master of the Modern Architecture , Alvar Aalto is listed among the most influential figures of the twenthieth century in this sector.
The library was built in Viipuri, a Finnish city at the time of the project, and located halfway between Helsinki and St. Petersburg. Today Viipuri is part of the Russian territory and has changed the name to Vyborg Viipuri. The building is considered one of the greatest expressions in Europe of the Modern Architecture.
The Viipuri library consists of two simple rectangular blocks that are offset from one another:
- on the largest block there are reading rooms, the children's library, a magazine and newspaper room and the book distribution desk.
- on the smaller and more extended block there is an archive, a small auditorium and administrative offices.
The reading room (which is located on two elegantly connected levels by a two-way staircase) is characterized by the absence of windows along the perimeter walls. Despite the lack of windows, the space is well lighted thanks to 57 circular openings in the flat roof. It is therefore possible to optimize the spaces as the absence of windows allows full use of the walls.
The architect Alvar Aalto explains the reasons of his choice:
The ceiling of the reading rooms and the rental room have 57 circular conical openings, 1.8 m in diameter, which serve as skylights.
The main principle is the following: the cones depht grants no light rays penetration since they are disposed with an angle equal to or less than 52 °. As a consequence, there is indirect lighting throughout the year. This arrangement guarantees the books to be protected from direct sunlight and the reader not to be disturbed by shadows or strong light, regardless of position when reading.
The internal surfaces of the cones reflect the day light projecting a clustered light towards the floor. Each seat in the reading room, illuminated by different cones, is therefore immersed in a composite light.
Let's see how, Alvar Aalto would have made the 57 circular openings in just a few simple steps thanks to a BIM software.

Circular conical openings– Villa Viipuri
Modelling skylights with a BIM software
Alvar Aalto could have faithfully reproduced the 57 circular conical openings with Edificius, the BIM software for the architecture.
The program's Magnetic Grid works as a guide for the positioning of the skylights.
We start off by creating the skylights through the Hole object and by positioning them along the grid intersections while following the previously defined guidelines with the 2D Magnetic Grid.
We proceed inserting another Hole with a larger radius. This will serve as a guide for inserting the final profile that we are going to implement.
From the project library we create the (extrusion) profile and through the multiple function we apply it as a frame to the holes.
We can create an additional Magnetic Grid (which we will overlay to the previously created one) in order to insert the skylight selected from the Objects library. Next, we insert a metal profile working as a frame for all the skylights.
Direct light introspection
Alvar Aalto's aim was to achieve an optimal internal lighting by preventing direct sunlight from entering any time of the year and since a diffused lighting is more suitable for reading ,
Such result was obtained by assessing the solar path height on the horizon according to the location latitudes together with a proper holes diameter sizing and height calculation on the roof.
Let's see how the Viipuri Library can be approached in terms of lighting design using Edificius, the architectural BIM software.
A BIM software could have been easily and immediately designed and assessed the library project, simply by inserting the latitude value of the project site. If the building would have been built, for instance, in Rome (thus inserting a different latitude value), the sunlight introspection would differ. By re-inserting the latitude coordinates of Viipuri we can immediately appreciate the path of sunlight and the value of Alvar Aalto's work.
Below a short explainer video summarizing the project steps.