*Lightness* is a beautiful characteristic that modern architects strive for in their projects. Read here how tensegrity structures evoke a feeling of lightness in their viewers.

Wilkinson On Lightness and Delicacy

Wilkinson, a principle architect at Wilkinson Eyre, hsa proposed many tensile and tensegrity structures. He is motivated to apply tensegrity principles in part due to the beautiful lightness that such structures impart. Wilkinson wrote about lightness [1], below are excerpts of that essay relevant to tensegrity.

"Lightness is not a technical term and cannot be measured in a finite way. It can be neither quantified nor specified but is a qualitative ingredient of modern architecture which is gaining momentum."

"The concept of ‘lightness’ concerns the physical weight and property of materials, but it relates as much to the visual appearance of structures, components and even spaces. It is a quality that comes from the form, composition and economical use of materials. It also relates closely to light and the way light is treated. Light in itself is a fundamental aspect of architecture, which probably reflects our innate instincts for survival, since we cannot exist without it. It follows therefore that buildings and structures which control light are pleasing to us. Poets muse on the way light plays on water and there is something romantic about the reflections and the dancing movements that come from ripples on the surface. Water can have a powerful impact on architecture by transmitting light and reflecting it onto adjacent surfaces. The magical experience of Venice with its beautiful palazzi reflected in the canals on a sunny day has inspired architects of past and current generations to incorporate water into their designs. Reflecting pools can add lightness and interest.

"Similar qualities come from the play of light on the surfaces of different materials and form is enhanced by the contrast of light and shade. Curved surfaces deal with light in an appealing way and a curved form will generally appear lighter than a corresponding square or rectangular form of the same volume. Projections and articulations pick up shadows and it is for this reason that traditional mouldings and decorative cornice details serve to enhance the appearance of heavy masonry buildings of the past. Transparent and translucent materials also play with light in an interesting way. Glass is an abundant material in our lives but it still holds almost magical qualities for us. Its crystalline nature catches the light so that it sparkles like jewels. Glass buildings, however, can appear either light and transparent or solid and monumental depending on the lighting conditions at the time of day. Transparency by definition allows space and light through, and seems to offer the kind of freedom that people want. We like to be able to experience the comforts of the inside whilst still enjoying the delights of the outside. We need light from the sun and we like to see it moving round throughout the day, for it helps us to orientate ourselves and to define time. So it follows that buildings which offer this ‘light freedom’ can be described as possessing lightness. Equally, materials, structures and building forms, which deal with light in a pleasing way, can be said to have ‘lightness’.

"The combination of steel and glass in modern buildings has significantly lightened their apparent weight and the same qualities can be achieved as effectively in multi-storey towers as with single-storey examples. Even lighter-weight structures can now be achieved with the more recently developed composite fibres and membranes. The really lightweight, high-strength materials such as carbon fibre are still expensive to use in large quantities but membrane fabrics, such as teflon-coated fibreglass, make economic sense for tented structures.

"Membrane structures perhaps offer the ultimate lightweight enclosure, the translucency of the fabric, the economy of materials and double curvature forms all adding to a sense of lightness. Recent developments with computer software have made form-finding much easier, so exciting new shapes are now possible and this is an area which we are interested in exploring further.

"For inspiration we look at nature, where all the most beautiful plants and flowers possess a quality of delicacy and lightness. There is something inherently appealing about the form of a flower’s petals or certain plant and tree forms. It may have something to do with their organic shapes, or it may relate to economy of material or clarity of function. Whatever it is, we feel comfortable with it. Nature is seldom clumsy and I can’t think of any examples of heavy monumentalism, with the possible exception of rock formations. It is a pity, therefore, that many of our manmade structures are so heavy and monumental. They seem to draw inspiration from cave-like structures and at best they may be grand or defensive but usually they appear pretentious and self-conscious. I prefer the aboriginal concept of treading lightly on this earth and I believe that this becomes ever more achievable with modern technology.

"To explain further the quality of lightness, we have only to look at images of a spider’s web, the interior structure of an airship, or a Naum Gabo sculpture. The spider’s web is principally light so that it can’t easily be seen whilst the interior of the airship has to be lightweight to achieve lighter-than-air lift efficiency.

"Tension structures invariably look lighter than compression structures and the elements of a structure which support tension forces are usually slimmer and lighter in weight. This is noticeable in bridges where long spans are required, and in particular with suspension bridges, where the slenderness of the deck and the apparent thinness of the supporting cables are accentuated by the scale of the horizontal spans that they connect.

"Colour is another factor which contributes to the experience of lightness. Of course, light colours help by simply reflecting the most light but the reflection of bright colours can have more exciting effects.

"Adriaan Beukers and Ed van Hinte, professors from the Faculty of Aerospace Engineering at the University of Technology in Delft, in their recently published book Lightness, refer to ‘the inevitable renaissance of minimum energy structures’. For them lightness is not just concerned with buildings, or aeroplanes, but with ‘the structure of all things made and grown’. Their main message is ‘the lighter the better’, which follows on from Richard Buckminster Fuller's dictum of ‘more with less’. But in architecture lightness is not only about weight but also appearance.

Other words for lightness

In biotensegrity, lightness is usually called porosity. In biological surfaces, porosity consists of individual openings and spacings or interconnecting pores. It occurs either at the substrate surface or in a way that completely penetrates throughout a bulk material.

In the creation of biomaterials, porosity can be created intentionally by a specific production process, such as sintering of beads, leaching of salt, sugar, or starch crystals, or knitting and weaving of fibers. On the other hand, porosity can also arise as a manufacturing artifact, for example, in casting procedures.

Links and References

[1] Chris Wilkinson's essay, "Lightness and Delicacy". His essay originally appeared in the practice monograph ‘Bridging Art and Science’ (Booth –Clibborn Editions, 2001).

Portal To Philosophy
A series on the philosophical implications of tensegrity.
Arithmetization, Frame, Lightness, Opposition, Space, Yin Yang
See also Castaneda