Architecture by a
“Form
Generation + Structural Optimization” program
Following
the completion of the Kyushu Shinkansen ShinMinamata Station, the author
was commissioned by the city of Minamata to design and built a monument
for the plaza in front of the station.
Two
purposes were involved. One was to design an object to express the ShinMinamata
Station, the new gateway to the city of Minamata.
The
other was to generate the object by a program that integrates form
generation and structural mechanics.
The
result, “ShinMinamata MON”, is probably the first architecture in the
world to be produced by a “form generation + structural optimization (aptimization)”
program.
The
generation of architecture by a program that solves specified criteria was
achieved by a previous program in the “INDUCTION DESIGN” series: the
Web Frame program used to design Subway Station
/ IIDABASHI (2000).
Two
issues remained to be addressed by successors to that program. One was
enhancement of the evaluation program, and the other was the incorporation
of structural mechanics. The former is addressed by the “Program of
Flow”, which is now under development. Integration with structural
mechanics was attempted with the “Wing” tower of
Subway Station / IIDABASHI, but
that program was never completed. The objective of the “ShinMinamata MON” program was to follow up on that attempt by
achieving integration with structural mechanics.
To
clarify that objective, this program does not deal with any materials
except structural members. The whole is a “pure” structure. The sizes
of members in the structure are selected according to stress. Thick
materials are used where stress is large, and thin materials are used
where stress is weaker. It is a structure that uses the right pieces in
the right places.
The
program allows the designer to apply loads at any point, in addition to
wind load and dead load. The loads used in actual calculations are shown
by the green poles at the top of the completed monument. The material is
thickness 32 mm steel, with widths limited to 120, 90, and 50. (A limited
number of members use thickness 38 mm steel.) Initially, the use of lasers
to carve out members from a single steel plate was considered, but that
idea was discarded because machining is difficult at these thicknesses.
Instead, we decided to use independent members welded together.
The program can also handle curved surfaces, but in view of the image of the monument as a gate it was decided to use a combination of flat surfaces for the actual structure. The generative program works by extending the growth pattern from the origin, so vertical surfaces are simply extensions of the pattern upward in the direction of growth.
Convergent evolution:
Similarity
of mechanisms, not an imitation of form
The
overall shape of the “ShinMinamata MON” may look like a grove of
trees. But it should be noted that this is by no means due to imitation of
the outward appearance of trees. This shape has no original, and quotes
from nothing (although the idea of a gate was present).
The
results of the specified generative rules simply turned out to be
something that looks like trees.
Strictly
speaking, they are not exactly like trees. (The branches of trees split
apart and only rarely come together again.) Nevertheless, the overall
impression is close to trees. The reason is that the specified generative
rules have something in common with the generative rules of trees. Even
aside from branches, it would be possible to discover similar structures
by looking at things such as leaf veins, roots, and our own bone structure
and bodily organs.
Of
course none of these things are imitations of tree branches. They are
structures born out of necessity, completely unrelated to each other,
which came to be similar in outward appearance as a result of a search for
optimal structures in response to given conditions and purposes. In
biology, this phenomenon -- where things like tree branches and bones,
which have completely different origins and materials, respond to similar
conditions for similar purposes and arrive at the same answer -- is known
as convergent evolution.
It
could be said that the “ShinMinamata MON” arrived at a form like
plants and bone structure through a kind of convergent evolution.
streaming
movie:
KeiRiki-1 image wmv 0:17
600kbps
480x320 15fps
Principles
of evaluation: How to produce good things?
The
form of the “ShinMinamata MON” came about as described above.
Therefore, simply by changing one of the input parameters to the program,
we can obtain a different form. In the same way, we can obtain a different
form by changing the settings of the “structural optimization
program”. The number of options is endless.
However,
this is not simply a multiplication of random options. Although it does
not include an evaluation process, the generative process is a combination
of generative principles, so that a certain degree of naturalness ( =
balance) can be observed. This is an interesting point.
We
could say that a kind of automatic regulation is at work in the rules.
There is no guarantee that the results will be beautiful, but oddly enough
only a few cases miss by a large margin.
The
questions “what is evaluation?” and “how can we obtain good
things?” are the themes of the “Program of Flow”, which is being
developed concurrently. The results of the “KeiRiki” program for “ShinMinamata
MON” may suggest possibilities for evaluation methods
(although for now they are nothing more than possibilities).
What
is better: Consistently obtaining solutions that meet the conditions /
relieving the constraints on imagination
What
is the significance of generating this structure programmatically?
The
same kind of shape could be drawn by hand, and it would also be possible
to assemble a structure of members with different thicknesses by
calculation. The actual structure could have been designed even without a
program like “KeiRiki”. So isn’t the program superfluous?
Of
course, you don’t need a program if all you want is build a shape that
you happen to like.
But
suppose that you must meet certain conditions. Suppose that the aperture
ratio of the whole must be below a certain value because of wind load. It
would be very difficult to take a shape that was simply drawn to please
and make it have a specified aperture ratio. It would be a process of
drawing and revising, repeated over and over until, if everything works
out, the conditions are met. Sometimes everything may not work out.
Suppose
that there are limits to the length of structural members, or limits to
the angles at which branching members can be welded. The same kind of
trial and error process would be needed, with no guarantee that an answer
would be found. This is the normal process of design. It is very rare that
the ultimate solution to meet all of the conditions that are imposed on
architecture appears from the start. Not only is it rare, but a slight
change to the solution can mean that it no longer meets the conditions. By
way of contrast, the program always meets the conditions. (Of course there
are always cases in which the conditions themselves are
self-contradictory.)
The
benefit of using a program is that that it allows you to obtain the kind
of solution you want, while at the same time solving the conditions.
Instead
of trying to unravel a tangled ball of string, until it seems to be too
much for one head to understand, humans can (or should be able to) devote
their energy to tasks on a higher dimension. The question is, what are
those tasks on a higher dimension?
