In the foreground, the performance of daylight on skyscrapers is examined, as they are the most controversial elements of the La Ville Radieuse proposal. Throughout the city's development, three versions of the skyscraper design can be found. The most important modification between these three versions of the design was the change from the uniform surfaces of the facades to planes with broadly serrated shapes. According to Le Corbusier, the benefit of these serrated shapes is that they form true light traps.

However, although the viability of daylight is resolved by the design of the sawn surfaces, the traps also allow light to enter from the sides, in addition to the main façade. This could result in better penetration of daylight into the room and increase the light level inside. In addition to the modification of the building blocks, Le Corbusier also proposed orienting the entire plan of La Ville Radieuse to the so-called heliothermal axis.

The merit of the skyscraper proposal is obviously the enormous amount of usable surface and open space it provides. The plot ratio of the skyscrapers is 3.8 and those of urban block 1 and 2 of the current city of Paris are, respectively, 1.5 and 2. Therefore, with the typical blocks of urban areas, 2 to 2.5 times more land is needed in order to provide the same amount of usable surface area of the La Ville Radieuse skyscrapers and without taking into account the amount of free space available in the proposal of the skyscraper.

Apart from the changes in orientation, Le Corbusier also reduced the construction height of the two housing blocks from 50m to 30m which represents around 40% reduction in usable surface area. It is speculated that the intention of this modification is to improve daylight performance in the housing blocks.

Le Corbusier would find it ironic, if not horrifying, that the fragmentary, organic, and uncontrolled generation of urban development processes that he always abhorred have carried out many of his design principles and emulated the images of his architecture in recent decades. Our contemporary city looks like his, with glass office towers and high-rise housing blocks, surrounded by grassy fields with curving paths, but without the order and urban focus he would like. Le Corbusier set a precedent for the war against darkness, overcrowding, unsanitary conditions and the pre-industrial fabric of the city, which he believed could be swept away by the heavy hand of the elite's master plan, which would instead provide new offices and residences with light, air, and greenery for an enlightened society. According to Robert Fishman, Le Corbusier simply "did not believe in fragmented planning", and considered that "the planner needs to open up spaces in which he is free to create his own urban order. He must be master of the entire environment. “Nothing can be carried out properly without an overall vision. "... Only then can a collective goal emerge, beautiful and effective, “worthy of the time.”

We are now very familiar with the criticism of his Plan Voisin and the Ville Radieuse, which are responsible for countless urban disasters executed in his spirit. Jane Jacobs's bitter rejection of Le Corbusier's "urban surgery" still resonates in the design profession: "His carefully organized skyscrapers in the park," she says, "are a terrible oversimplification of urban order. Their rigid separation of functions makes true diversity impossible; their inhuman large scale and empty spaces kill the vitality of an attractive city." In Le Corbusier's defense, he is to blame for many works not executed by much less skilled architects, with much less capacity to understand "the whole." Ultimately, however, his plans for the city of tomorrow are nothing more than diagrams to carry a radical message, which have proven disastrous in the wrong hands. Jacobs's response to projects inspired by Le Corbusier's vision is a reversal of his original polemic: "high-rise housing and business projects are what die as “unhealthy islands” of the modern city, and the dense, complex districts that Le Corbusier wanted are the true sources of urban health.

Why, then, are we still bringing their projects to this day? Perhaps he had enough intuitions about the way in which he would comfortably take on the city. After all, he was carrying out the next mainstream, encompassing the technological and social change that was required. Ironically, we are still captivated by the ambitions and shapes that characterize their plans, which are, of course, of their time, not ours. The world has witnessed great changes since the 1920s, and is influenced by an entirely new set of technological phenomena and socio-political conditions. Therefore, it would be logical for us to try to make sense of our time, and to project new schemes (with fewer harmful effects) accordingly.

The conclusions of this study seem to indicate that La Ville Radieuse is not as radiant as previously thought. Comparison of the density and potential sunlight between La Ville Radieuse and the urban blocks of present-day Paris suggest that the propositions made by Le Corbusier about this ambitious urban plan cannot be entirely true. The proposal may be good in terms of transport and the availability of large open and green space; however, daylight management does not appear to be better than traditional daylighting systems. Daylight performance in skyscrapers is particularly poor. The results seem to suggest that the skyscraper proposal is not, in fact, an option for the effective design of the central region of Paris. On the other hand, both “back-to-back” housing and “cellular” housing seem to perform well in daylight, but the surface area on which they can be used in these designs is much less occupied, which could be a drawback.

The effect of the heliothermal axis is ambiguous. Aunque Le Corbusier lo consideraba como uno de los principios más importantes en el diseño urbano, su efecto potencial sobre la luz del día no se ha justificado en el estudio, el cual podría ser un poco sesgado si el efecto del eje heliotérmico es puramente evaluado en términos de la iluminación; The results may be different if other factors such as thermal energy loss and gain were taken into consideration. Después de todo, La Ville Radieuse, racional y sistemático plan urbanístico diseñado por Le Corbusier, no parece ser una opción efectiva para el diseño de la densidad actual sobre todo y el rendimiento de la luz del día. Por otra parte, el modelo tradicional, que demuestra potenciales de luz similares, y posiblemente una mayor densidad, podría ser una mejor opción para París.

In the foreground, the performance of daylight on skyscrapers is examined, as they are the most controversial elements of the La Ville Radieuse proposal. Throughout the city's development, three versions of the skyscraper design can be found. The most important modification between these three versions of the design was the change from the uniform surfaces of the facades to planes with broadly serrated shapes. According to Le Corbusier, the benefit of these serrated shapes is that they form true light traps.

However, although the viability of daylight is resolved by the design of the sawn surfaces, the traps also allow light to enter from the sides, in addition to the main façade. This could result in better penetration of daylight into the room and increase the light level inside. In addition to the modification of the building blocks, Le Corbusier also proposed orienting the entire plan of La Ville Radieuse to the so-called heliothermal axis.

The merit of the skyscraper proposal is obviously the enormous amount of usable surface and open space it provides. The plot ratio of the skyscrapers is 3.8 and those of urban block 1 and 2 of the current city of Paris are, respectively, 1.5 and 2. Therefore, with the typical blocks of urban areas, 2 to 2.5 times more land is needed in order to provide the same amount of usable surface area of the La Ville Radieuse skyscrapers and without taking into account the amount of free space available in the proposal of the skyscraper.

Apart from the changes in orientation, Le Corbusier also reduced the construction height of the two housing blocks from 50m to 30m which represents around 40% reduction in usable surface area. It is speculated that the intention of this modification is to improve daylight performance in the housing blocks.

Le Corbusier would find it ironic, if not horrifying, that the fragmentary, organic, and uncontrolled generation of urban development processes that he always abhorred have carried out many of his design principles and emulated the images of his architecture in recent decades. Our contemporary city looks like his, with glass office towers and high-rise housing blocks, surrounded by grassy fields with curving paths, but without the order and urban focus he would like. Le Corbusier set a precedent for the war against darkness, overcrowding, unsanitary conditions and the pre-industrial fabric of the city, which he believed could be swept away by the heavy hand of the elite's master plan, which would instead provide new offices and residences with light, air, and greenery for an enlightened society. According to Robert Fishman, Le Corbusier simply "did not believe in fragmented planning", and considered that "the planner needs to open up spaces in which he is free to create his own urban order. He must be master of the entire environment. “Nothing can be carried out properly without an overall vision. "... Only then can a collective goal emerge, beautiful and effective, “worthy of the time.”

We are now very familiar with the criticism of his Plan Voisin and the Ville Radieuse, which are responsible for countless urban disasters executed in his spirit. Jane Jacobs's bitter rejection of Le Corbusier's "urban surgery" still resonates in the design profession: "His carefully organized skyscrapers in the park," she says, "are a terrible oversimplification of urban order. Their rigid separation of functions makes true diversity impossible; their inhuman large scale and empty spaces kill the vitality of an attractive city." In Le Corbusier's defense, he is to blame for many works not executed by much less skilled architects, with much less capacity to understand "the whole." Ultimately, however, his plans for the city of tomorrow are nothing more than diagrams to carry a radical message, which have proven disastrous in the wrong hands. Jacobs's response to projects inspired by Le Corbusier's vision is a reversal of his original polemic: "high-rise housing and business projects are what die as “unhealthy islands” of the modern city, and the dense, complex districts that Le Corbusier wanted are the true sources of urban health.

Why, then, are we still bringing their projects to this day? Perhaps he had enough intuitions about the way in which he would comfortably take on the city. After all, he was carrying out the next mainstream, encompassing the technological and social change that was required. Ironically, we are still captivated by the ambitions and shapes that characterize their plans, which are, of course, of their time, not ours. The world has witnessed great changes since the 1920s, and is influenced by an entirely new set of technological phenomena and socio-political conditions. Therefore, it would be logical for us to try to make sense of our time, and to project new schemes (with fewer harmful effects) accordingly.

The conclusions of this study seem to indicate that La Ville Radieuse is not as radiant as previously thought. Comparison of the density and potential sunlight between La Ville Radieuse and the urban blocks of present-day Paris suggest that the propositions made by Le Corbusier about this ambitious urban plan cannot be entirely true. The proposal may be good in terms of transport and the availability of large open and green space; however, daylight management does not appear to be better than traditional daylighting systems. Daylight performance in skyscrapers is particularly poor. The results seem to suggest that the skyscraper proposal is not, in fact, an option for the effective design of the central region of Paris. On the other hand, both “back-to-back” housing and “cellular” housing seem to perform well in daylight, but the surface area on which they can be used in these designs is much less occupied, which could be a drawback.

The effect of the heliothermal axis is ambiguous. Aunque Le Corbusier lo consideraba como uno de los principios más importantes en el diseño urbano, su efecto potencial sobre la luz del día no se ha justificado en el estudio, el cual podría ser un poco sesgado si el efecto del eje heliotérmico es puramente evaluado en términos de la iluminación; The results may be different if other factors such as thermal energy loss and gain were taken into consideration. Después de todo, La Ville Radieuse, racional y sistemático plan urbanístico diseñado por Le Corbusier, no parece ser una opción efectiva para el diseño de la densidad actual sobre todo y el rendimiento de la luz del día. Por otra parte, el modelo tradicional, que demuestra potenciales de luz similares, y posiblemente una mayor densidad, podría ser una mejor opción para París.