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Perforated skin – shade for the Piraeus Tower – Final review

The idea was to create a new facade for the Piraeus Tower, a kind of second skin which would react to the surrounding elements, as the buildings around, the different views and the noise. For this a perforated skin was created which would be open to the views and become thicker according to the sun, as well as redefining or creating new public spaces at different places of the tower. Being seen from all around, the aim of this new facade is also to be elegant and have an interesting geometry and characters to work as an icon for the Piraeus and Athens.

First some analyses were done, both about views and noise, where the attractive views were the acropolis, the mountains, the park nearby and the entrance of the port. The result can be seen in the image map, where the white being where you have the best views and the black as the less interesting views. For the noise, the big road on the south is the biggest source of noise, and then we can find the car street on the east, the market on the north and the pedestrian street on the west. The result can also be seen in the image map, where the white represents the calmer areas, and the black the noisiest. It was considered that the noise decreases with the height, but also that the base of the tower works as a noise barrier, which protects the low part of the tower. These different analyses where then put together to get one image map with the whiter corresponding to the more calm areas with the best views. This will then inform where to place the attractor points to deform the grid of the perforated skin.

The grid was deformed according to these attractor’s points, becoming denser where the closest from these points it was. The contraction can be controlled wit parameters which can be varied and changed, in order to control how much the grid becomes denser or not.

The skin also works with a variation in the thickness, which allows controlling the sun exposure of the glass facade behind. The thickness is a factor of the size of the perforations, the higher and the wider the openings are, the thicker the skin becomes. The thicker part is always oriented according to the facade, with the upper part, as well as either the left or the right side becoming thicker. This factor between the size of the perforations and the thickness car be varied and controlled by changing the values.

The aim of this new skin is also to create new public spaces or redefine the existing ones. Therefore the different parts of the tower are punctually linked in between, which provides nice partly shaded public spaces. On the ground floor, the space around the shops are redefined with the skin working as arcades, with main accesses at the corners, giving a nice atmosphere for shopping. On the top of the base, a restaurant with a nice shaded terrace takes place, as well as on the top of the tower, the skin provides a nice spot, partly covered, to look at the whole city, also in the hot days of summer in Athens.

Different tries and studies where made for the corners, with the first try where the corner was thicker in the middle and bumping out, and then trying to take the corner a bit inside, to obtain a nicer result with a smooth continuity of the facade, which simply turns around at the corner, becoming a bit lighter at these places.

The skin is divided in smaller elements, which would be prefabricated and assembled together. All of them are different, but they are assembled always in the same way.

The skin is made of composite material, with fibber glass. The elements are prefabricated and joint together, working and alternating between two different types of joints, either glued -where the structure can work in traction and allow the skin to cover the big surfaces of the terrace or the roof- or fixed together with a metal element, which can allow the tolerance that this kind of structure needs and facilitate how to position the elements when building the facade.

These elements are punctually fixed to the slabs with some thin metal elements and supported by the existing structure. A gap is created in between the two structures, which varies according the orientation of the facade (smaller in the north and wider in the south) as well as where the stairs take place. This gap increases the shading effect of the perforated skin, with the shade becoming even more important.

The perforated shading skin allows only a part of the light to come in, and protect the isolated glass facade from hot sun exposure. It also creates an interesting complexity of the light entering in the building, creating a nice atmosphere either for working or for restaurants.

The project could be brought further on, with more study and answer to how to exactly build this skin. One could imagine another material, which could allow not freezing the thickness and the size of the perforation; but something which could be more interactive and could allow the skin to breathe and move according to the sun, and might be cheaper and even lighter than composite material.

Presentation panel:

deformed perforated skin – pin-up

A perforated skin, non-structural, which reacts to the environment – such as the views and the noise – in the 2 dimensions of the grid and to the sun in the 3rd dimension, with its thickness changing according to the size of the perforations.

Analysis of the views, looking at the parc, the entrance of the port, the mountains and the acropolis. Each facade look at two of these objects. The result of the analysis is the result of this both views for each facade. The whiter it is, the best view you have, the darker it is, the less good view you have.

The same kind of analysis was made for the noise around the tower. The main road on the south, the car street and the pedestrian streets on the east and west, as well as the market on the north were recognised as source of noise. The result depends of the nearest source of noise of each facade. The tower is protected on the bottom from the base which in section works as a barrier from the noise. It is also taken as a influence the idea that the higher we get, the more the noise decreases. The whiter it is, the less noise there is.

On the upper drawings we can see all the analysis together, with also the projection of the surrounding buildings on the facade. The more white it is, the best view and the less noise we get, as in opposite the darker it is, the less we can see and the noisier it is. This will determine where the skin will contract and have denser and smaller perforations (where there is nothing to see and a lot of noise) or where the skin would open to the views and the calm areas.

Here the deformed grid, which follow attractors points determined by the results of the analysis. The idea is that the skin open itself on the bottom to create a clear  entrance to the tower from the roof of the base. There is also the idea to punctually connect the different parts of the grid. The roof is partely covered and the tower is attached to the base at some places.

An idea of what could be this deformed grid, with the first try of connecting punctually the different surfaces.

The perforated skin would be built out of smaller elements, prefabricated and in composite material. The pieces would be always different in size and in volumetry, but the system to place them together will be always the same.

The repartition of these different prefabricated pieces.

The skin is not only two-dimensionnal or flat, the idea is to work with an important thickness, which would reduce the solar exposure of the first skin (glass facade) behind. The aim is also to create a very interesting and attractive geometry for this icon tower.

The first try of the volumetry and the thickness of the skin. The idea is that the skin becomes thicker at the upper corner and the left/right corner (depending from where the sun comes from)  of each perforation. The width of this thickness is determined according to the length and the width of each perforation. The two other corners of the perforations would be a determined by a factor of the two other.

Question about image sampler / analysis


I’m trying to work with image samplers to use my analysis in my project. I have a gray scale image and I want to visualise and be able to analyse it with sth showing me where it is the lighter and where it is the darker.

I have been able to do that and get circles to show me the differences…

but I’m not sure to understand exactly how to set the number in the image sampler settings and in the grid I’m using…

because I do not get the same result if I make a small grid or if I make a bigger grid, from the real size of the facade.

I have more details with the small grid than with the bigger one. And I don’t get the same result for the smaller/bigger circle…

Does anyone knows why I have this problem/difference??

question?? how to find the longest vector


I have a group of vectors / or circles and I would like to be able to only use the longest / smallest. I was able to sort out the biggest/smaller lenght of the vectors or the areas of the circles, but then I just have a number, that I cannot use to  figure out which vector/circle it correcponds to.

question PATCH in grasshopper


Does anyone can tell me if there is a command on grasshopper which make the same as “patch” in Rhino ?? I want to make a surface out of POINTS which are not planar…

Thank you!!

concrete sunscreen for the giant – mid-term review

The Piraeus tower in Athens is well exposed to all part of the city but also very exposed to the sun, as it the only high building of the surroundings. For this purpose the idea is to create a double skin facade with a second skin working as a sunscreen open to light, air and views. The aim was also to create a more dynamic façade and an icon for the city seen from far away. Both ideas are translated in the solution of a concrete lace-like façade which provide shade to the first skin.
A space of more than one meter between the concrete perforated skin and the isolated glass façade create a so-called “chimney effect” where the hot air has room to rise and cool the surface of glass windows.

The grid of this structure is determined by the exposure of the sun and the orientation of each façade. Two concepts lead to the final result of the grid: searching the best sun protection, the curves are first turned back from the sun and secondly become denser to the top, where the sun exposure is the highest. The perforations become smaller and less dense when going to the top. The third dimension increases the sun protection. Indeed the smooth surface becomes thicker where the perforations become bigger. So it will be thicker at the bottom of the tower and thinner at the top.

Concrete was chosen as it has good isolation properties but also gives the sensation of a solid shelter with character. White colour concrete is used to absorb the less sun but also to shine far away and work as a landmark of the city, welcoming the new incomers arriving in the Piraeus port.

The façade is self-supporting and works in compression based on the ground, where the contact surface area allows a certain weight for the structure which can be distributed irregularly through the whole. The structure is divided in X-shaped prefabricated elements, which are shifted against each other, which will be assembled on site.



I’ve a question in grasshopper. Is it possible to create a curved surface out of points which are not in the same plan and not in a certain order? If yes could you tell me how??

It would help me a lot!!!

Thank you!

x4_Prefabricated element – density of perforation

The two ideas for the project: create a movement which would give a sensation of rotation at the base and a sensation of verticality for the tower; and work with a density of perforations decreasing the higher you get, in order to have something more open to the bottom, where people can pass through, and a more closed facade in the top, which will have a bigger strength when seen from far away.

The chosen solution is to work with a sort of tended structure, like a net which would become denser at the top, and have a curved grid to give the sensation of movements.

To create this grid, I first started to define points where the different curves of the grid would start and end. On the side of the tower, the points are always situated where the slabs are. There is a rhythm of one curve every two slabs. Then the segments of the top and the bottom are divided in equal distances to give the other points needed.

Then I gave a certain regular thickness to the curves, creating polygonal perforations, which will be reduce the more you go to top of the tower, in order to play with the density.

I also want to play with the third dimension, where the skin will become thicker the biggest the perforations are. So it will be thicker at the bottom of the tower and thiner at the top. The idea is to use this third dimension to create shade and protection from the sun.

I tried to understand how to be able to built this structure. The first idea was to use light weight concrete, which would have been cast-in-place, on site. The problem was that the variations of the grid was too important and the perforations to different to be able to find a module that could be repeated and be efficient.

I changed then idea, and try to find how I could divide the structure in smaller pieces, which would be connected always in the same way, with the same kind of simple joint. The solution here is to divide the structure in small crosses, which come one against the other one and are just added to the other. The problem is that the joints are quite visible and important. And also very repetitive.

Finally, I choose to divide the structure in another way, and work with slightly bigger element. The idea is to shift the different cross, to mix better the different elements, in order to feel one structure. The cross go always along three perforations, we find different pieces for the sides or the edges of the tower. The solution and the place where you have joints seem less repetitive and less visible.

These different elements could be prefabricated and place together on site. Different material could be possible, as light weight concrete, metal or even composite material.

Cape Sundew

question: how to create polyline out of a grid?


I’m trying to design my project in grasshopper… (the file is in svn with the date 100323..)

I’ve been working first in Rhino, setting the point for my grid where I wanted. Then I connected the different points together in order to create a grid. But I’ve only been able to create lines in between them and not curves!!

-> Can you help me to set curves instead??

Then, I offset my grid, and I would like to be able to get polylines of the each “perforation” of my grid.

-> Do you have an idea how I could do it?

And last question, are you at any time in the lab tomorrow, if we need some help?

Thank you!