Lamella Flock

Abstract

The research project Lamella Flock questions how tectonic systems are usually formed and proposes self-organization as a means for future design. Lamella Flock investigates the possibility of designing as well as physically producing free-form interlinked structures based on multiple and circular dependencies.
The research takes its point of departure in the intersection between traditional wood craft, computer science, and a digital non-standardized production. Through computation and methods of self-organization the project investigates the structural abilities of the wooden Zollinger system; a structural lamella system distributed as a woven pattern of interconnected beams. By introducing an understanding of these beam elements as autonomous entities with sensory-motor behaviour the geometrically rigid Zollinger system is transformed into structures describing free-form surfaces.
By implementing dynamic processes, Finite Element Calculation, material and production constraints, and real-time interactive modelling in a hybrid environment Lamella Flock explores how to design and build with such a system. Hereby the agent system negotiates between design intent, tectonic needs, and production while creating a direct link between the speculative and its materialization.

Full text

Lamella Flock
Martin Tamke
CITA, Centre for Information Technology and Architecture,
Royal Danish Academy of Fine Arts, School of Architecture
Jacob Riiber
CITA, Centre for Information Technology and Architecture
Royal Danish Academy of Fine Arts, School of Architecture
Hauke Jungjohann
Knippers Helbig Advanced Engineering
Mette Ramsgard Thomsen
CITA, Centre for Information Technology and Architecture
Royal Danish Academy of Fine Arts, School of Architecture
Abstract. The research project Lamella Flock questions how tectonic systems are
usually formed and proposes self-organization as a means for future design.
Lamella Flock investigates the possibility of designing as well as physically
producing free-form interlinked structures based on multiple and circular
dependencies.
The research takes its point of departure in the intersection between traditional
wood craft, computer science, and a digital non-standardized production. Through
computation and methods of self-organization the project investigates the
structural abilities of the wooden Zollinger system; a structural lamella system
distributed as a woven pattern of interconnected beams. By introducing an
understanding of these beam elements as autonomous entities with sensory-motor
behaviour the geometrically rigid Zollinger system is transformed into structures
describing free-form surfaces.
By implementing dynamic processes, Finite Element Calculation, material and
production constraints, and real-time interactive modelling in a hybrid
environment Lamella Flock explores how to design and build with such a system.
Hereby the agent system negotiates between design intent, tectonic needs, and
production while creating a direct link between the speculative and its
materialization.

M. Tamke, J. Riiber, and H. Jungjohann
Figure 1. Renderings of two generated models with diverse characteristic
.
1 Non-Linear Processes in Architectural Design
During the last 20 years a new design practice has emerged in which architects
become the developer of bespoke design environments that allow dynamic
interfacing between design intention and contextual information [Kolarevic 2005,
Shwitter 2005, Burry 2005]. This design practice has allowed for projects of high
degrees of complexity that directly engage contexts such as day light [Whitehead
2005], spatial envelope [Goulthorpe 2008] or structure [Linsey 2001].
The organization of the related information is the domain of the building
discipline. While the sources, nature and importance of these parameters are highly
diverse the predominant strategy organizes them in carefully weighted linear
flows. Parametric systems help to organize this flow of information, wherein one
level of instructions is based on the previous.
This hierarchical approach allows for order and overview, yet has problems
accounting for the complexity of design solutions that arise when multiple and
highly interrelated parameters are incorporated.
We are surrounded by the success of this top-down strategy, as well as its
failures. The downfalls have led to a wide interest in alternative design strategies
such as bottom-up and performance based design methods [Kolarevic 2005].
Utilizing generative interactive procedures these methods relate to a notion of
form-finding with direct interaction and feedback to the designer as in the practice
of Gaudi, Frei Otto or Isler. Where these systems optimize mainly towards single
goals (e.g. withstand gravity), computation allows optimization towards multiple
goals of diverse nature. In this research we introduce the concept of an aware
design model and ask how design can take place in environments that are
characterized by multiple and circular dependencies governed by bottom-up
principles?

Lamella Flock
2 Zollinger – A Lamella Wood System
The Zollinger construction is a type of lamella roof construction [Allen 1999] that
was invented in the 1920s in order to create wide spanning constructions out of
short pieces of timber (Figure 2 and 3).
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Figure 2 and 3. F. Zollinger and an original Zollinger Roof system in Merseburg, Germany.
The lamella’s structural principle consists of a crisscrossing pattern of parallel
arches of relatively short members. These are hinged together to form an
interlocking network in a diamond pattern. The ingenuity resides within two
constituents: Firstly, the efficient joint system that minimizes the amount of shared
meeting points allowing for simple assembly, secondly, the structural strength
given by the interwoven beams (Figure 4).

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Figure 4. Principal pattern of the Zollinger lamella structure.
Where similar systems, such as reciprocal frame systems [Popovich 2008],
usually form barrel or dome shapes, work from the AA [Hensel and Menges
2007], Shigeru Ban [Tristan, Self, and Bosia 2007] and Oliver Baverel [Popovich
2008] demonstrates the principal ability of the systems to form different shapes
using the flex of the material, tolerances in the joint geometries and changes in
beam orientation. In this bottom-up approach each element is threaded individually
as it acts autonomously in a larger formation

M. Tamke, J. Riiber, and H. Jungjohann
Our own investigations revealed that freeform structures can be manually
crafted from straight bamboo sticks by exploitation of tolerances in the joint. Yet
this method relies purely on skill in crafting and negotiation with the physical
model. The translation of this craft-based process into an architectural planning
practice was a main concern of the investigation. This required the development of
a parametric system that would allow control, anticipation and fabrication of
geometry in relevant scale and tolerance. How could the non-linear relationships
of the system be modelled within a computer?
3 Free Form Wood Structures and Previous Experience
Previous research on mass customized parametric wood constructions [Tamke,
Thomsen, and Riiber 2008] indicated that digital production can provide the
sought after flexible, effective fabrication of easily assembled wood beams. This
approach is based on the conjunction of computation, digital fabrication, and
traditional craft techniques. Herein modern CNC wood joinery machinery allows
the cutting of monolithic joints in high speed and variable geometry (Figure 5).
These joints allow for fast assembly as they incorporate self registering
geometrical properties such as contemporary industrial snap fit joints [Schindler
2009]. The improved understanding of forces within massive wood, in its
monolithic joints as well as in its assembly as structural systems through Finite
Element systems [Holzner 1999] allows for new applications of traditional wood
crafts. The combination of computational capabilities with digital fabrication
allows therefore the introduction of craft related knowledge into contemporary
practice that was previously bound to the skill and knowledge of the executing
craftsperson.
Figure 5. Wireframe view of the customized monolithic Tenon joints used in the
construction.

Lamella Flock
4 Investigating Freeform Lamella Systems
In the initial stages of the research the distribution and computing of elements
where investigated looking for the most suitable method of controlling the system
and its non-linear relationships.
The lamella structure was at first distributed on pre-modelled surfaces. This
presented two problems: When following a free-form surface all beam endpoints
should be on the surface. Since all endpoints also connect to the midpoints of other
beams this criterion cannot be met. Secondly this top-down approach lacked the
possibility of exploring the performance of the structural principle. How would the
rigidity of the reciprocal relationship between beams affect the scope of shapes
possible?
The conclusion to use bottom-up approaches instead, gave at first problems in
controlling the system. The elements were here structured through a rule based
linear distribution where element were sequentially inserted. Due to the fact that in
a networked lamella system one element is affecting all neighbours the linear
distribution led to extreme and unpredictable conditions. This impeded design
control but did result in compelling morphologies (Figure 6).
Figure 6. Output of a rule based distribution of lamella elements
The problems within the mentioned experiments made it possible to state the
requirements of our lamella system: A bottom-up process with the ability of
dynamic non-linear interaction where different design possibilities could be
explored. We introduced an understanding of the structure as a self-organizing
system of entities possessing a simple set of behavioural properties and relations to
each other.
5 An Outline of Self-Organization
Theories of self-organization where originally developed in the context of physics
and chemistry to describe the emergence of macroscopic patterns out of processes
and interactions defined at a microscopic scale. Later it was found that these ideas

M. Tamke, J. Riiber, and H. Jungjohann
could be extended to the simulation of social insects to show that complex
behaviour may emerge from interactions among individuals that exhibit simple
behaviour. Here social insect colonies where viewed as decentralized problem-
solving systems, comprised of many relatively simple interacting entities
[Bonabeau, Dorigo, and Theraulaz 1999].
This relies on the idea that a group of agents may be able to perform tasks
without explicit representations of neither environment nor other agents, and
where planning may be replaced by reactivity [Coates and Carranza 2000]. By re-
contextualizing these abilities into numerous fields of knowledge powerful tools
for developing dynamic and intelligent systems emerged.
The advantages of using self-organization to solve problems reside in a
flexibility to function in changing environments and an ability to function even
though some entities may fail to perform. The disadvantages can be located in the
bottom-up approach to programming such systems. Here the paths to problem
solving can never be predefined but are always emergent and result from
interactions among entities themselves, as well as between entities and their
environment. Therefore, using self-organization to solve a problem requires
precise knowledge of both the individual behaviour of agents and what interactions
are needed to produce a desired global effect [Bonabeau, Dorigo and Theraulaz
1999].
6 The generated lamella system, structure and behaviour
Our computer program is based on the interaction of four line segments coming
together in a spiralling motion. In this way each entity exhibits within itself the
non-linear relationship that also defines the global structure aimed at.
To initialize the program consists in determining the amount of entities, their
sizes, and a preliminary distribution of these as a diagonal grid in space. The grid
can either be coherent or fragmented depending on the desired modelling process.
Positioning entities in space are in both cases done by either defining a distribution
of point coordinates or loading a previously saved model into the system. This last
feature allowed us to create models that could be evaluated through other tools and
changed accordingly.
While running, the system is controlled through four behavioural algorithms
that accumulate vector information (Figure 8). A method inspired by the division
into goal types found in the simulation of flocks, herds and schools [Flake 1998].
Each algorithm produces directions and velocities that interact to produce the
overall movement and transformation of an entity:
1. Movement towards neighbours: When not representing a corner or an
edge each entity has four neighbours. By measuring the distance and
direction from endpoints of line segments to a neighbour connection
point, vectors are calculated. These vectors are added and weighted to
calculate a mean vector by which all points in an entity are moved.
2. Orienting towards neighbours: By altering the configuration of angles

Lamella Flock
between segments each element tries to orient its segments towards their
neighbours. A segment is in this way sought to be aligned with the
trajectory towards its destination.
3. Stretching towards neighbours: Through the above orientation a
segment will, within a certain tolerance, be able to stretch to connect to a
neighbour. This is allowed when the orientation is correctly aligned and if
it is happening within a predefined size limitation of a segment.
4. Scale entity: Each entity has the ability to scale up and down while
keeping its proportions. This allows for a global push/pull effect within
the lamella network.
Figure 8. Initial state and the 4 main behavioural principles of Lamella Flock
Additionally production related constraints were introduced into the program.
At the scale of the individual beam elements this means that the computation
restricts the beam sizes and intersection angles to the specifications allowed by the
machinery used for production. Also, the program is informed by the fact that two
beams cannot share the same meeting point on a third beam, i.e. even though all
non-edge beams will be connected to two other beams midway along their length,
drilling for joints needs separate space for both connections. The program deals
with this by slightly offsetting the shared meeting points of every element away
from each other.
The generative design process was in this way informed by its implementation
and realization in 1:1.
The global behaviour occurring from these functions produces a network of
entities that attempts to obtain the shape of a surface. The global configuration is
continuously and non-lineally renegotiated until a stable result is achieved.
7 A hybrid system
Experience [Tamke and Ramsgard 2009] has shown that in the context of
architectural design a combination of generative and interactive modelling is
practical. We introduced the possibility of manually manipulating entities while
the system is running. This results in a tool where changes in the configuration of a
surface can be made by altering local conditions, while self-organization deals
with the global consequences of these actions (Figure 9).

M. Tamke, J. Riiber, and H. Jungjohann
Figure 9. Formation and interaction of a lamella structure within the Processing interface
Actions include the ability to move an entity in any direction or change its
scale, as well as fixate it in a given position. This last feature forces the
surrounding network to adapt to the new conditions. Colour coding of elements
and a navigational diagram helps to maintain an overview of these manipulations.
Precision and localization of the design model where given through a millimetre
based unit space and the ability to link in 3D models of the site (Figure 10).
Figure 10. Processing interface with model of the ROM exhibition site

Lamella Flock
8 Implementation
The interface allows the model to interact dynamically with and inside an
environment given by site, program, production and material. Changes to the
environment through manipulation are instantly answered by the model through
shape change. These transformations appear to the designer as a result of an
internal reflection rather than direct answer. In this way designing starts by
learning about the distinct character of the model and its behaviour.
The model exchanges through customized information transfer with different
specialized tools: for structural FE-Analysis with Sofistik or for the generation of
production data to Generative Components. The output can be adjusted to different
model scales ranging from design speculation to 1:1 realization through machine
code for Hundegger wood joinery machines (Figure 11, 12). Intense
communication and testing through prototypes were crucial to determine the
adequate types and dimensions of joints, fasteners, bearing and bracing for
fabrication and assembly strategies.
Figure 11. Labeled Non-standard wood beams ready for assembly
Feedback was integrated into the model which was becoming noticeably aware
of its placement in the building process – its environment. The incoming
information was handled in a pragmatic way where new insights were either
encoded as internal conditions in the generative code or the visual interface was
used for constraining the SO system.

M. Tamke, J. Riiber, and H. Jungjohann
Figure 12. 1:1 Demonstrator at the ROM gallery Oslo / Norway
The intense preparation allowed us to exploit the capacity of digital fabrication
and self registering joinery, demonstrated by only 3.2 hours of cutting time
and two days of overall assembly of a structure consisting of 80 individualized
beam elements.
9 Conclusion
The hybridization of generative processes and interactive modelling proposes a
solution for integrating self-organization within architectural design and shows
that non-linear systems can be used as a design tool. Here the different modelling
methods are not mutually exclusive and work in parallel rather than in succession
with individual strengths and weaknesses. Where programming is able to structure
processes and relations that otherwise are beyond human capabilities specific
design intentions are hard to test or change. Here manual interfacing rather than
programming opens a space for design speculation where various constraints can
be applied in an easy to handle fashion. Further research into the construction of
customized user interfaces for hybrid dynamic-interactive processes might prove
valuable for opening new territories for architectural design
The project shows that self-organization is capable of negotiating in an early
architectural design context, characterized by interrelated requirements. It allows
implementing global design intent as well as information regarding production,
detail and material. The advantages of this are apparent in the speed and accuracy
by which structures could be realized in 1:1 (Figure13). The open nature of the

Lamella Flock
approach allows it to include an extended set of information, creating extended
awareness of e.g. surroundings, gravity and tectonic stress.
Figure 13. Detail of lamella demonstrator in 1:1
Acknowledgements
The Lamella system was only possible through support by HSB Systems,
Hundegger GmbH, Trebyggeriet.no, Knippers and Helbig Advanced Engineering
and Prof. Christoph Gengnagel/ TU-Berlin.
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Authors’ address:
Martin Tamke (martin.tamke@karch.dk)
Jacob Riiber (jacob.riiber@karch.dk)
The Royal Danish Academy of Fine Arts,
School of Architecture
Philip de Langes Allé 10
DK - 1435 Kbh. K
Denmark
Hauke Jungjohann (h.jungjohann@knippershelbig.com)
Knippers Helbig Inc.
134 Spring Street, Suite 601,
New York, NY 10012, USA