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From Nature to Fabrication: Biomimetic Design Principles for the Production of Complex Spatial Structures


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In the current paper the authors present a biomimetic design methodology based on the analysis of the Echinoids (sea urchin and sand dollar) and the transfer of its structural morphology into a built full-scale prototype. In the first part, an efficient wood jointing technique for planar sheets of wood through novel robotically fabricated finger-joints is introduced together with an investigation of the biological principles of plate structures and their mechanical features. Subsequently, the identified structural principles are translated and verified with the aid of a Finite Element Model, as well as a generative design system incorporating the rules and constraints of fabrication. The paper concludes with the presentation of a full-scale biomimetic prototype which integrates these morphological and mechanical principles to achieve an efficient and high-performing lightweight structure.
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Reprinted from
Volume 28 · Number 1 · 2013
From Nature to Fabrication:
Biomimetic Design Principles
for the Production of Complex
Spatial Structures
Riccardo La Magna, Markus Gabler, Steffen Reichert, Tobias Schwinn,
Frédéric Waimer, Achim Menges and Jan Knippers
It is widely recognized that biological systems
represent a valid source of inspiration for the solution
of given technical problems. Still, the vast range of
morphological diversity between organisms inhabiting
the same environment suggests that a standard and
optimal solution does not exist, but rather different
strategies may perform optimally under certain
circumstances. This is obviously true as all living
species have developed their own survival strategies,
whether structural or behavioural, albeit living in
similar contexts. The main questions that arise when
trying to apply design principles derived from biology
to engineering and architecture are essentially: 1.
which principles are better suited for the addressed
topic and 2. how to bridge the gap between the
biological role model and its technical implementation.
Extensive literature exists on the topic explaining the
From Nature to Fabrication:
Biomimetic Design Principles
for the Production of Complex
Spatial Structures
Riccardo La Magna1, Markus Gabler1, Steffen Reichert2, Tobias Schwinn2,
Frédéric Waimer1, Achim Menges2and Jan Knippers1
1ITKE – University of Stuttgart
2ICD – University of Stuttgart
(Submitted on 22/10/2012, Accepted on 22/12/2012)
ABSTRACT: In the current paper the authors present a biomimetic design
methodology based on the analysis of the Echinoids (sea urchin and sand
dollar) and the transfer of its structural morphology into a built full-scale
In the first part, an efficient wood jointing technique for planar sheets of
wood through novel robotically fabricated finger-joints is introduced together
with an investigation of the biological principles of plate structures and their
mechanical features. Subsequently, the identified structural principles are
translated and verified with the aid of a Finite Element Model, as well as a
generative design system incorporating the rules and constraints of fabrication.
The paper concludes with the presentation of a full-scale biomimetic prototype
which integrates these morphological and mechanical principles to achieve an
efficient and high-performing lightweight structure.
International Journal of Space Structures Vol. 28 No. 1 2013 27
theoretical methodology to identify the biomechanical
and functional rules, understand the underlying
principles, perform the abstraction from the biological
model and finally provide their technical
implementation [Vincent 2009].
The current paper presents a case-study project by
systematically exposing the methodological steps that
enabled the identification of the biomimetic principles
and their successful transfer to a full-scale prototype
(Fig. 1). The research project is based on a biomimetic
approach for the development of construction systems
and computational design processes, which builds on
previous investigations on the theoretical
methodology for extracting morphological principles
related to structural and architectural matters.
In the first part of the paper an overview of the
identified design strategies and their characteristics
are discussed. Both Top-Down and Bottom-Up
*Corresponding author e-mail:
implemented process sequences for the identification
of the appropriate biological principles and their
abstraction are explained (Fig. 2), along with
the robotically fabricated design solution and the
structural behaviour of the chosen role model. The
results are finally discussed both in context of their
28 International Journal of Space Structures Vol. 28 No. 1 2013
From Nature to Fabrication: Biomimetic Design Principles for the Production of Complex Spatial Structures
architectural design potential and in the larger context
of biomimetic design on the one hand and computer-
aided manufacturing on the other.
In the realm of biological organisms, the abundance of
shape is a direct consequence of the evolutionary process
that living beings undergo to constantly meet changing
environmental conditions. The morphological features
of each individual are the result of the constant
interaction between the organism and its environment,
under the influence of which populations of living
beings adapt through selection and breeding, thus
enhancing their probability of survival. The result is a
compromise satisfying partially conflicting requirements
which limits the potential of natural selection as an
optimizing agent [Knippers and Speck 2012]. Moreover,
typical optimization tasks in engineering science
primarily focus on the determination of a set of
parameters that produce the fittest outcome chosen from
an array of different solutions by implementing
deterministic algorithms that assure convergence to the
problem. The same cannot be said about biological
systems, which achieve a high level of structural
performance through redundancy and local
differentiation of their constituent features.
Despite the inability in biology to identify a single
and precise solution to a given problem, it is still
perfectly reasonable to assume that living organisms
have developed through time highly efficient
Figure 1. (a) Detailed view of the developed finger joint
connection; (b) top view of the built full scale prototype.
6 Bionic product
1 Technical problem
6 Bionic product
2 Search for biological
3 Identification of
appropriate principles
4 Abstraction, detachment
from biological model
5 Test technical feasibility
and prototyping
3 Understanding the
2 Biomechanics, functional
morphology, and anatomy
4 Abstraction, detachment
from biological model
5 Technical implementation
1 Biological research
Bottom up
Top down
(a) (b)
Figure 2. (a) Bottom-up process of biomimetic research (biology push); (b) top-down process of biomimetics (technology pull).
[Knippers and Speck 2012].
J. Knippers, M. Gabler, R. La Magna, F. Waimer A. Menges, S. Reichert and T Schwinn
International Journal of Space Structures Vol. 28 No. 1 2013 29
strategies to overcome the environmental challenges to
which they are exposed. For instance, in the specific
case of sea urchins and sand dollars (a sub-species of
sea urchins), the peculiar arrangement of the plates
that compose their skeleton is found to be optimal
when considered from a plate point of view. Also, the
finger-like jointing system that sea urchins and sand
dollars have developed to connect their constituent
plates serves as a perfect technique to resist the shear
forces acting across the edges. These two principles
have been the main driver to the development of the
current research project.
2.1. Technology pull: wood jointing using
The developed fabrication technology of connecting
wooden plates at various angles using finger joints has
been one driving aspect for the presented research.
Transferring this technology in combination with a
biologically inspired, performative plate arrangement
into a pavilion including its own specific architectural
requirements and constraints was the overall aim of
this project [Krieg et al. 2011].
The ancient technique of joining planar elements at
edges with multiple often interlocking teeth has been
employed over about 3500 years [Kirby 1999]. Whereas
wood was one of the most commonly used construction
materials in pre-industrial times due to its availability,
the importance of wood was decreasing until very
recently. Now, triggered by the environmental
challenges the building sector is facing, timber as a
regionally available and renewable resource receives
the attention of the construction industry again. While
steel joints have become more convenient to join wood
parts, the connection of these very different materials
often causes additional problems such as different
temperature behavior and corrosion.
Joining wood sheets using force and form fit finger
joints results in a connection with a high structural
capacity that withstands normal and in particular shear
forces without the use of additional fasteners. To
fabricate this material-consistent and efficient
connection using traditional techniques, mostly very
intensive manual labor was required. With increasing
labour costs, manually fabricated, wooden
connections have become less and less affordable (Fig.
3-a). While the use of additional mechanical jigs (Fig.
3-b) allowed reproducing equal finger joint pattern
repetitively in an economical way, this has limited the
connections to orthogonal connections or at least a
very small number of different angles.
The robotic fabrication process (Fig. 3-c) developed
for this project opens up the design space through the
ability to efficiently fabricate differentiated finger
joints with variable angle arrangements (Fig. 4)
[Menges 2011] [Krieg et al. 2011].
Figure 3. (a) Manual fabrication of dovetail joints; (b) tools
for machine-based fabrication of different finger joints
restricted to a 90° connection; (c) newly developed robotic
fabrication technique.
30 International Journal of Space Structures Vol. 28 No. 1 2013
From Nature to Fabrication: Biomimetic Design Principles for the Production of Complex Spatial Structures
2.2. Biological push: echinoides’ plate
The shell of the sea urchin consists of a modular system
of polygonal plates, which are linked together at the
edges by finger-like calcite protrusions (Fig. 5-c). Shell
action is very close to plate action because a finely
faceted plate polyhedron is nothing but a slightly
discontinuous shell, stabilized only by shear forces,
acting along the edges. High load bearing capacity is
thus achieved by the particular geometric arrangement
of the plates and their joining system.
The plates of the sea urchin’s skeleton are organized
according to an overall principle that allows the
organism to resolve the competing requirements of
resisting external loads and shocks on the one hand
and the necessity of letting the growth process take
place on the other. This principle is that a maximum of
three plates meet in one point (Fig. 5-b). By following
Figure 4. Robotically fabricated finger joints. (a) connecting
two plates with different material thickness at a specific
angle; (b) prototype with differentiated finger joints; (c)
spatial connection of finger-joined plates.
Figure 5. (a) Close-up of a sea urchin’s test; (b) schematic top
view of a sea urchin’s test showing the plates’ outlines and
arrangement; (c) microscopic view of a plate edge showing the
calcite projections similar to finger joints [Seilacher 1979].
J. Knippers, M. Gabler, R. La Magna, F. Waimer A. Menges, S. Reichert and T Schwinn
International Journal of Space Structures Vol. 28 No. 1 2013 31
this principle, any pure plate structure (i.e. systems
composed of just plates and hinges along the edges of
connection) will be inherently stable, whereas any
variation from this arrangement pattern will result in a
deformable and kinematic structure similar to origami.
Thanks to this arrangement, the plates are stabilized
by resisting internal forces which lie in the plate itself.
Each face of a pure plate structure carries plate forces
only, i.e. plates must not rely on carrying bending
moments and torsion for their own stability. On the
other hand, the lines of support enable the transmission
of normal and shear forces but no bending moments
between the joints. This property allows the sea urchin
to grow without interfering with the transfer of
stabilizing forces, as the direction of growth will be
perpendicular to the shear lines, hence perpendicular to
the direction of the stabilizing shear forces.
2.3. Transfer of geometric morphologies
As a methodology for transferring the cellular
morphology of the sand dollar, including its rule of three
connecting plates, into a generative computational
design tool, the targeted implementation of a Voronoi
diagram is suggested such that each Voronoi cell
represents the polygonal boundary of a cellular entity
[Zachos 2009]. The custom developed computational
tool was subsequently organised into two representation
models: a flat 2-dimensional topological map (Fig. 6-a)
and a 3D geometry model of the same topology
(Fig. 6-b). The plate-cell components’ 3-dimensional
arrangement is thereby embodied through a two-tier
hierarchical system: on the higher level, the Voronoi
diagram describes the global topological arrangement
of the cells; on its lower the cells’ plates locally
reference the topological map. These plates constitute
the 3D model and form the basis for the fabrication of
the full-scale pavilion (Fig. 6-c).
On the lower hierarchy level, each cell consists of
multiple plates. Through the connection of each
polygon’s vertex with its cell centroid, the polygon
becomes triangulated (Fig. 7). The number of resulting
triangular faces around the polygon centroids can be
described through the Schläfli symbol {p,q}, where p
represents the number of sides of the internal
polygons, and qthe number of triangles located
around the centroid corresponding to the number of
Voronoi cell edges (Fig. 7-a).
Aphysically driven digital environment was set up to
design an interactive, generative form finding process
for the physical full-scale prototype (Fig. 1-b) [Menges
2012]. Using a spring relaxation method, every polygon
side is set to relax into an approximate equal rest length.
The relaxation transforms the 2D topological
representation into a 3D mesh (Fig. 7-b). With changing
Schläfli symbols, the structure changes its Gaussian
curvature between positive (e.g. Schläfli symbol {3,5}),
negative ({3,7}) and zero ({3,6}). This topological
modification in a physically driven environment allows
responding to structural and architectural demands like
entrances, light openings etc.
Additional gravity forces have been applied during
the relaxation process to enhance the shape in its
Figure 6. (a) 2D topology model; (b) 3D geometry model;
(c) full-scale prototype.
32 International Journal of Space Structures Vol. 28 No. 1 2013
From Nature to Fabrication: Biomimetic Design Principles for the Production of Complex Spatial Structures
structural performance (Fig. 6-b). This added force
causes an inherent directionality in the cell’s local
shape and hence an anisotropic structural performance
along the main load bearing directions (Fig. 6-c).
Over the past few years, architects and designers have
been increasingly exploring the design of freeform
complex surfaces. The task challenges engineers to
design and develop efficient structural systems both
from an economic and ecological point of view.
Traditionally, the assembly procedures of structural
members into a whole construction have mostly lead
to massive details caused by the need of transferring
bending moments between the joints. The aim of the
bionic approach presented here was to find an
effective way to build spatial structures by assembling
panels which transfer only normal and shear forces
between the edges. Another important feature of the
project, which is also commonly pursued in structural
design, is a great level of redundancy, as in the case of
failure of single plates the structure still needs a good
residual load capacity.
3.1. Biomechanics and abstraction
The most important feature of the sea urchin’s plate
morphology is its compliance to the 3-plate principle,
meaning that it is fully trivalent and can thus be
regarded as a pure plate structure [Wester 2002]
[La Magna et al. 2012]. The stability of polyhedral
structures is uniquely determined by the valency of
their vertices, where the valency indicates the number
of structural elements converging at one node.
According to the type of elements that make up the
structure we may distinguish between lattice and plate
systems, meaning that the first ones are materialised
by the edges whilst the latter by the faces of the
polyhedron. Systems with triangular faces which only
rely on bars and joints make up pure lattice structures,
whereas systems composed of just Y vertices (only
three edges meeting at one point) which depend on
plates and hinges along the edges are called pure plate
structures [Wester 2002]. Such structures are said to
comply with the 3-plate principle.
The morphology of the sand dollar was abstracted
to CAD models and analysed with FE simulations.
With different panelised arrangements, the influence
on the structural behaviour of the plates and of the
joints was evaluated. The plates could be connected
only by three degrees of freedom, meaning only
normal, lateral and shear forces. The FE results
confirmed that for pure plate structures of arbitrary
geometry and loading no bending moments occur in
the joints, but the lateral forces in the edges and the
global deformation of the structure were greater than
the equivalent continuous model with bending
moment transferring capacity. Nonetheless, the
advantages of designing joints that would not transmit
bending moments were still predominant.
Concerning the aspect of the geometrical influence,
concave plates had to be avoided as they lead to high
stress concentrations in the corners for overall loading
Figure 7. Strategy assuring convex and flat plates for
anticlastic geometries; (a) polygonal base mesh; (b) normal
translation of centre; (c) resultant frustum through truncation.
J. Knippers, M. Gabler, R. La Magna, F. Waimer A. Menges, S. Reichert and T Schwinn
International Journal of Space Structures Vol. 28 No. 1 2013 33
and boundary conditions (Fig. 8). This side-effect was
assessed for anticlastic surfaces with planar panels.
That is the reason why in nature, and particularly in the
morphology of sea urchins, such kind of patterns do
not exist and the plate morphology is always convex.
Thus, the structural arrangement and its principle with
hexagonal planar surfaces are only applicable for
geometries with positive Gaussian curvature.
However, one research aspect of the project focused
on the investigation of how a plate structure can also
be adapted to surfaces with negative Gaussian
curvature and still comply with the 3-plate principle.
By raising the level of each individual cell, it was
possible to achieve the desired design freedom in each
curvature direction (Fig. 7). This was possible as in the
lower hierarchical level no hexagonal plates were
arranged. With the addition of different hierarchical
levels, it was then possible to pursue the arrangement
of the sea urchin’s plate structure and to apply it to a
range of different freeform surfaces.
3.2. Implementation of experimental
To run a first static analysis, it was necessary to
determine the characteristic values of the connection
and to demonstrate the mechanical principle of the
finger joints. With different setups the connections
were tested on their lateral, normal and shear force
transmission and on their stiffness behaviour (Fig. 10).
Very good results were achieved for the shear strength
and low bending stiffness of the rotational degrees of
freedom. Said results were later incorporated in the
Finite Element model by defining the failure criteria of
the joints.
The mechanical behaviour of the finger joints was
compared with several biological investigations of
biomechanical behaviour of the sea urchin structure
and the connection of the plates [Ellers et al. 1998].
Biologists have proven that the plates of the sea urchin
are only strengthened by flexible collagenous fibre.
The perforated calcite plates are attached to each other
at sutures by ligaments to transfer the normal and
lateral forces. In the case of the developed connections
of the research pavilion, the ligaments were
implemented by a PU flexible adhesive.
3.3. Technical implementation
Besides constructional and organizational principles,
hierarchy is a fundamental property of biological
structures. The assembling of plates and cells is
organized on a two-level hierarchical principle. On the
first level, the finger jointed plywood sheets form a
Deformation Von mises stress Morphology
Figure 8. Abstraction of plate structure principle.
Figure 9. Hierarchical levels. Figure 10. Experimental tests for shear behaviour.
34 International Journal of Space Structures Vol. 28 No. 1 2013
From Nature to Fabrication: Biomimetic Design Principles for the Production of Complex Spatial Structures
cell. On the second hierarchical level, a simple bolt
connection joins the cells together, allowing the
assembling and disassembling of the pavilion. Due to
the arrangement of the bolts in the cells and of the
material characteristic of plywood and its low
stiffness, a transfer of bending moments between the
cells could be minimized by creating a hinged
connection. Within each hierarchical level only three
plates - respectively three edges – meet at one point,
therefore assuring bending-free edges for both levels
(Fig. 9).
Arequirement for the design, development and
realization of the complex morphology of the pavilion
was a closed, digital information chain linking the
project’s model and Finite Element simulations. Form
finding and structural design were closely intertwined.
An optimized data exchange scheme made it possible
to repeatedly read the complex geometry into a Finite
Element program to analyse and modify the critical
points of the model. The FE setup was modelled with
plane shell elements and lines of axial springs acting in
the direction of the edges of connection between the
plates (Fig. 12). Based on a FE Model with more than
10.000 spring elements to simulate the finger-jointing
of the cell elements, custom tools for the FE Solver
had to be developed and implemented (Fig. 11).
The test results put under evidence the high
construction capacity of the biological role model and
its aptness to be transferred to a built prototype. Unlike
traditional lightweight construction, which can only be
applied to load-optimized shapes, this new design
principle could be applied to any custom geometry.
The high lightweight potential of this approach is
evident as the pavilion, despite its considerable size,
Structural analysis self weight
Structural analysis self weight + wind loads (w) Structural analysis self weight + wind loads (w) Structural analysis self weight + wind loads (w) Structural analysis self weight + wind loads (w)
Structural analysis self weight Structural analysis self weight Structural analysis self weight
Figure 11. Different steps of geometric variations and FE feedback.
Figure 12. (a) Bending moments progression in the structure;
(b) FE plot of the structure.
J. Knippers, M. Gabler, R. La Magna, F. Waimer A. Menges, S. Reichert and T Schwinn
International Journal of Space Structures Vol. 28 No. 1 2013 35
could be built out of 6.5 mm thin sheets of plywood,
which resulted in a great material saving. Therefore,
above all the structure had to be secured against uplift
due to wind suction forces.
One of the main challenges when applying biomimetic
principles to architecture and structure remains the
transfer of the identified morphological principles into
fabricational principles and their subsequent physical
implementation. Recent advances in CNC Technology
and particular the second advent of robotic fabrication
[Bechthold 2010] suggest that the pre-fabrication of
building elements with highly differentiated
geometries - one of the constituent properties of
natural systems - becomes economically feasible.
4.1. Fabricating finger joints
Based on initial studies that explored strategies for the
robotic fabrication of finger joints, a custom tool was
developed with one of the industrial partners that allows
the cutting of finger joints with the front of the tool as
opposed to the widely used flank milling in CNC
contour cutting which typically results in the rounded
corners for concave tool paths. Contrary to this flank
milling strategy, the cut with the front of the tool results
in a form-fitting finger joint connection (Fig. 13-c).
Further studies in the fabrication of finger jointed
plates at varying angles indicated that in order to be
able to manufacture convex as well as concave plate
connections without manually repositioning the work
piece, an additional external axis is necessary to
synchronously reorient the work piece such that the
perimeter of the plates can be accessed from all sides
and angles by the 6-axis industrial robot (Fig. 14).
Conversely, the geometric characteristics intrinsic
to the plate and joint system suggest that this particular
bio-informed material system requires at least 7 degree
of freedom (DoF) for its fabrication. As such, the
research project is not only an investigation into how
the expanding solution space of advanced CNC
fabrication machinery can be meaningfully explored
utilizing biomimetic design strategies, but it also
introduces the biological concept of morphospaces to
denote what can theoretically be and has empirically
been produced with respect to the specific parameters
of a given machinic configuration [Menges and
Schwinn 2012].
4.2. Parameter space translation
In addition to the biomimetic principles that inform the
design process as part of the generative rule set, the
specific parameters of robotic fabrication are
translated and implemented in the computational
design tool. One of the main aspects of this translation
is the mathematical description of the spatial relation
between work piece and milling effector through
trigonometry and linear algebra.
The different tool paths for the fabrication of a plate
are a function of the angles between the plate and its
Figure 13. Three steps of the finger joint fabrication process;
(a) milling the plate’s outline; (b) milling the edge’s miters;
(c) spot facing the finger joints.
36 International Journal of Space Structures Vol. 28 No. 1 2013
From Nature to Fabrication: Biomimetic Design Principles for the Production of Complex Spatial Structures
neighbouring plates (Fig. 15), which can yield different
structural and geometric properties. E.g. the contact
surface between plates decreases for angles close to 90
degrees providing less contact area. However, the
length of the indentation of the finger joints increases
towards 0 and 180 degrees resulting in extremely sharp
finger joints that compromise structural stability and
accuracy of fabrication.
Ultimately, the geometric plate relations, finger joint
geometric properties, and the specific end effector
geometry, consisting of milling tool, chuck and spindle
bounding box, confine the preferred range of the joint
angles to approximately 15 to 165 degrees (Fig. 16). As
embedded parameters in the computational design tool
these fabricational constraints directly inform the
design process.
4.3. Robotic fabrication programming
The fabrication model is derived and parametrically
linked to the geometry and design model that was
generated with respect to the fabricational constraints
outlined above. The programming of the robotic
fabrication consists of a custom process including the
topological analysis of the plate connectivity, which is
the basis for automated tool path generation in form
of an ordered point cloud as well as the automated
extraction of machine code into an ISO-based CNC
format (ISO 6983) (Fig. 17). The machine code
contains the Cartesian coordinates of the tool path
sequence which typically has to be translated through
reverse transformation into the joint space of the
machine. Due to the inherent complexity of the 7-axis
inverse kinematics and to ensure a reliable and
repeatable fabrication process, this step is
implemented in a dedicated post-processor as
opposed to relying on the automated calculation of the
robot control unit during runtime [Brell-Çokcan and
Braumann 2010].
Joint path
Tool direction vector
Miter path
Tool direction vector
Outline path
Tool direction vector
(a) (b)
P0 P0
P8 P10
P11 P13
Figure 14. Machine setup - a six-axis industrial robot
connected with a separate turntable as an external axis.
Figure 15. (a) Geometric representation of the three different tool paths; (b) close-up of the finger joint milling routine.
Figure 16. The finger joint fabrication is geometrically constrained due to possible collisions between the machine and the stock
J. Knippers, M. Gabler, R. La Magna, F. Waimer A. Menges, S. Reichert and T Schwinn
International Journal of Space Structures Vol. 28 No. 1 2013 37
The automation of the machine code programming
becomes a prerequisite for the efficient fabrication of
highly differentiated structures [Bechthold 2010]. In
contrast to process-specific CNC machinery, the
industrial robot can be considered a platform on
which a variety of fabrication processes can be
implemented that, in turn, require a higher level of
numerical control and machine code programming. In
this sense, the complexity of the fabrication task shifts
from the specificity of the machine to the specificity
of the control. Our custom programming strategy
suggests a highly specific application-based solution
to CAM for a generic fabrication platform offering a
vast solution space such as industrial robots.
4.4. Fabrication logistics and assembly
The Research Pavilion consists of more than 850
geometrically unique, robotically fabricated birch
plywood plates joined at their edges by more than
N7 G0 X-752.554 Y-176.411 Z86.926 I0.783 J-0.392 KD.483
N8 G0 X-869.936 Y-117.537 Z86.926 I0.783 J-0.392 KD.483
N9 G1 X-651.296 Y-121.87 Z-3.078 I0.783 J-0.392 KD.483 F4000
N10 G1 X-938.879 Y-77.177 Z-3.078 I0.783 J-0.392 KD.483 F4000
N11 G1 X-547.055 Y504.654 Z-3.078 I0.783 J-0.392 KD.483 F4000
N12 G1 X-524.639 Y549.345 Z-3.078 I0.783 J-0.392 KD.483 F4000
N13 G1 X-533.279 Y553.881 Z14.431 I0.783 J-0.392 KD.483 F4000
N14 G0 X-415.895 Y494.803 Z86.925 I0.783 J-0.392 KD.483
N15 G0 X-536.441 Y337.63 Z89.929 I0.311 J-0.803 K0.508
N16 G0 X-583.102 Y508.135 Z13.929 I0.311 J-0.803 K0.508
N17 G0 X-579.435 Y498.665 Z-3.452 I0.311 J-D.803 K0.508 F4000
N18 G1 X-532.809 Y516.723 Z-3.462 I0.311 J-D.803 K0.508 F4000
N19 G1 X-5.061 Y719.908 Z-3.462 I0.311 J-D.803 K0.508 F4000
N20 G1 X38.566 Y737.962 Z-3.462 I0.311 J-D.803 K0.508 F4000
N21 G1 X34.899 Y747.432 Z13.769 I0.311 J-D.803 K0.508 F4000
N22 G0 X61.56 Y625.924 Z89.929 I0.311 J-D.803 K0.508
Figure 17. Tool path generation; (a) topological map of a
module; (b) geometric representation of the generated tool
paths; (c) translation of the tool path to CNC-Code.
Figure 18. Prototype’s assembly process; (a) each module is
prefabricated in the workshop; (b) the modules are finished
and weatherproofed; (c) assembly of the modules on site.
38 International Journal of Space Structures Vol. 28 No. 1 2013
From Nature to Fabrication: Biomimetic Design Principles for the Production of Complex Spatial Structures
100.000 individual finger joints. The high potential of
the integrated design principles is demonstrated by the
fact that the entire pavilion could be built exclusively
out of 6.5 mm thin sheets of plywood, despite its
considerable size: 200 cubic meters (7050 cubic feet)
of gross volume are enclosed by only 2m3(70.5 cft) of
wood. Following the robotic fabrication, the plates are
assembled into the 59 individual building elements
that are finished and weather-proofed (Fig. 19).
The pavilion consists of two interior spaces that
emphasize the experience of the constructional logic:
the main space is characterized by the differentiated
openings in the double layer modules as well as by its
prominent relation to the park; an interstitial space is
framed by the gradual separation of the double layered
structure into two single layers. Together the two
interior spaces exemplify the capacity of the system to
not only incorporate geometric differentiation but also
to enable differentiated spatial and programmatic
experiences (Fig. 19).
In this paper, a biomimetic design methodology has
been introduced combining novel robotic fabrication
techniques for finger joints with biological principles
into a fabricated full scale architectural prototype. One
of the goals was the opening up of the solution space
of a traditional timber manufacturing technique, while
maintaining the inherent advantages of the finger
joints properties.
Biological role models have been analysed, their
topological and structural principles identified and
transferred into generative, geometric rules. Such
rules formed the basis for the development of a
computational tool integrating the sea urchin’s
biomimetic principles, the architectural and structural
requirements, and the fabrication constraints for
design exploration. Along these parameters, a specific
architectural case study has been developed in the
form of a pavilion. For an efficient connection
between the design information model and the input
data of the robotic manufacturing facilities, a custom
finger joint with integrated tool path generation was
developed. Simulation of the mechanical behaviour
was developed to predict the structural capacity of the
biologically inspired construction.
The Research Pavilion was a collaborative project of
the Institute for Computational Design (ICD – Prof.
Achim Menges) and the Institute of Building
Structures and Structural Design (ITKE – Prof. Dr. Jan
Knippers) at Stuttgart University, made possible by the
support of a number of sponsors including: KUKA
Roboter GmbH, OCHS GmbH, KST2 Systemtechnik
GmbH, Landesbetrieb Forst Baden-Württemberg
(ForstBW), Stiftungen LBBW, Leitz GmbH,
MüllerBlaustein Holzbau GmbH, Hermann Rothfuss
Bauunternehmung GmbH, Ullrich & Schön GmbH,
Holzhandlung Wider GmbH.
Responsible for the concept and development:
Oliver David Krieg and Boyan Mihaylov. Project
team: Peter Brachat, Benjamin Busch, Solmaz
Fahimian, Christin Gegenheimer, Nicola Haberbosch,
Elias Kästle, Yong Sung Kwon, Hongmei Zhai.
Scientific development carried out by: Markus Gabler
(project management), Riccardo La Magna (structural
design), Steffen Reichert (detailing), Tobias Schwinn
(project management), Frédéric Waimer (structural
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Figure 19. (a) The double-layer responds to structural and
architectural requirements; (b) the spatial experience changes
as the interior lighting emphasizes the double-layer’s depth.
J. Knippers, M. Gabler, R. La Magna, F. Waimer A. Menges, S. Reichert and T Schwinn
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... Ainsi, l'aboutement, technique connue de la construction bois, semble posé avant l'introduction de l'oursin dans l'espace de conception (cf. Krieg et al., 2011;Riccardo La Magna et al., 2013;Schwinn et al., 2012). Les concepteurs parlent en effet d'un technological push ou d'un processus top-down au sens où la biologie est interrogée dans un second temps, à partir d'un projet déjà partiellement déterminé 12 . ...
... En particulier ceux de WernerNachtigall (2003, p. 7-10) et de Ture Wester (2016 cités dans(Krieg et al., 2011;Schwinn et al., 2012;Ricardo La Magna et al., 2012;Riccardo La Magna et al., 2013;Krieg et al., 2014). À noter que Nachtigall s'appuie lui-même sur les travaux de Ture Wester qu'il cite, mais aussi sur les travaux de sa doctorante UtePhilippi (voir Philippi & Nachtigall, 1996).17 ...
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Rapport de recherche - URL: ABSTRACT : This work follows a first study of biomimetic design on the case of the Beijing stadium by Herzog and de Meuron. In the continuity of this work, biomimetic architectural design is analyzed from a cognitive point of view on design activities and processes. It uses the concepts of "models" and "scales" from the architecturological theory as a framework for analysis and takes as a case study the series of timber pavilions built between 2011 and 2019 through the collaboration between the Institute for Computational Design (ICD) and the Institute for Tragkonstruktionen und konstruktives Entwerfen (ITKE) of the University of Stuttgart. This case study allows to examine the specificity of biomimetic design processes carried out in an academic context and with the collaboration of biologists. Finally, it allows to uncover specific problems related to the analogies between nature and architecture and to reflect on a usage scenario for a design support tool based on an ontology. // RÉSUMÉ: Ce travail fait suite à une première étude de la conception biomimétique portant sur le cas du stade de Pékin de Herzog et de Meuron. Dans la continuité de ce travail, la conception architecturale biomimétique est étudiée à partir d’un point de vue cognitif sur les activités et processus de conception. Elle mobilise comme cadre d’analyse les concepts de « modèles » et d’« échelles » de la théorie architecturologique et prend pour cas d’étude la série de pavillon bois construite entre 2011 et 2019 issue d’une collaboration entre l’Institute for Computational Design (ICD) et de l’Institut für Tragkonstruktionen und konstruktives Entwerfen (ITKE) de l’Université de Stuttgart. Ce cas, permet d’étudier la spécifité de processus de conception biomimétique réalisé en contexte académique et avec la collaboration de biologistes. Enfin, il permet de mettre à jour des problèmes spécifiques relatifs aux analogies entre nature et architecture et de réfléchir à un scénario d’usage pour un outil d’aide à la conception basé sur une ontologie informatique.
... Another constructive strategy is shell segmentation with flexible sutural ligaments. This solution can be observed in organisms, such as the turtles and sea urchin skeletons, which inspired new building constructions and industrial design products [64][65][66]. ICD/ITKE Research Pavilions and permanent buildings are outstanding examples of architecture inspired by echinoid skeletal structures [64][65][66]. The Stuttgart pavilion (2015-2016) effectively demonstrates the scaling of different structural echinoid details: (1) division into modules, (2) material differentiation, (3) double layer modules, and (4) modules interconnected by finger-joints and collagen fibres ( Figure 1). ...
... This solution can be observed in organisms, such as the turtles and sea urchin skeletons, which inspired new building constructions and industrial design products [64][65][66]. ICD/ITKE Research Pavilions and permanent buildings are outstanding examples of architecture inspired by echinoid skeletal structures [64][65][66]. The Stuttgart pavilion (2015-2016) effectively demonstrates the scaling of different structural echinoid details: (1) division into modules, (2) material differentiation, (3) double layer modules, and (4) modules interconnected by finger-joints and collagen fibres ( Figure 1). ...
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Organisms and their features represent a complex system of solutions that can efficiently inspire the development of original and cutting-edge design applications: the related discipline is known as biomimetics. From the smallest to the largest, every species has developed and adapted different working principles based on their relative dimensional realm. In nature, size changes determine remarkable effects in organismal structures, functions, and evolutionary innovations. Similarly, size and scaling rules need to be considered in the biomimetic transfer of solutions to different dimensions, from nature to artefacts. The observation of principles that occur at very small scales, such as for nano- and microstructures, can often be seen and transferred to a macroscopic scale. However, this transfer is not always possible; numerous biological structures lose their functionality when applied to different scale dimensions. Hence, the evaluation of the effects and changes in scaling biological working principles to the final design dimension is crucial for the success of any biomimetic transfer process. This review intends to provide biologists and designers with an overview regarding scale-related principles in organismal design and their application to technical projects regarding mechanics, optics, electricity, and acoustics.
... With its shape resembling roughly a flattened spheroid, the geometry can be also seen as an eggshell envelope with seamless curvature. Given that biological systems may suggest solutions for technical problems [4] and that a standard optimal solution can be achieved by using different strategies performing optimally under specific circumstances [5], the proposed design is an expression of natural continuity that blends with the architectural brute force and intentionally strain is explored sequentially in all of its forms (axial, shear, bending, torsion). This combined loading approach as a design decision is achieved through a natureinspired scheme with imperfections and asymmetries resulting in a structure in state of self-stress. ...
Conference Paper
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Based on Kiesler's perception of space and the idea of continuity, the design proposal from DARC (Digital Architecture Research Centre at Kent School of Architecture and Planning) follows a nature-inspired scheme discussing the notion of continuity of force through the study of combined loading. Geometric intuitive methods are used to examine and determine axial forces, bending moments, torsion values and deflections. These include the use of Kangaroo, mesh subdivision, and traditional and latest developments in Graphic Statics. The study originally explores the use of the Doo-Sabin subdivision method for determining force, and, through seeking parallelisms of structural design with biological systems, aims to detect the benefits and limitations of expanding the application of advanced Graphic Statics and Graphic Kinematics methods for moments and deflections in nature-inspired design vocabularies.
... Although constrained by limits related to energy and available resources, many structures of echinoid skeleton are optimized in terms of functional performances and, consequently, can be used as role models for bio-inspired solutions in building constructions and various industrial sectors: from architecture and civil engineering to biomedical and new materials (Perricone et al., 2020). Attracted by the echinoid skeleton, Professor J. Knippers Magna et al., 2013;Grun et al., 2016). An interesting example of bioinspired design of engineering products was instead realized by a group of engineers from the Jacobs School of Engineering, University of San Diego, California, in close collaboration with expert marine biologists. ...
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The manuscript addresses the ideation of superficial appearances for emerging materials, taking as reference natural subjects of the plant world. The appearance of new materials offers the opportunity to achieve renewed experiences. The objective is to design appearances for predetermined substrates in the laboratory, assessing the contributions of surface design to the users’ perceptual construct. The methodology includes aspects related to bionics, selection and analysis of natural subjects; ideation of proposals; definition of substrates; prototype manufacturing; and user studies. The conclusions are oriented towards the implication of the natural referent in user evaluations, as well as the use of digital technologies in the ideation process.
... 17,18 The ongoing research yields novel industrialized production models exhibiting various automation, scalability, and efficiency. 13,[17][18][19][20][21][22] Continuing this line of research, we investigate materialaware automation strategies for RCFW adapted to the structural and functional needs of lightweight construction. The challenge to develop smarter RCFW construction methods extends our research scope beyond file-to-factory application, into the field of cyber-physical systems (CPS). ...
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Digitization and automation are essential tools to increase productivity and close significant added-value deficits in the building industry. Additive manufacturing (AM) is a process that promises to impact all aspects of building construction profoundly. Of special interest in AM is an in-depth understanding of material systems based on their isotropic or anisotropic properties. The presented research focuses on fiber-reinforced polymers, with anisotropic mechanical properties ideally suited for AM applications that include tailored structural reinforcement. This article presents a cyber-physical manufacturing process that enhances existing robotic coreless Filament Winding (FW) methods for glass and carbon fiber-reinforced polymers. Our main contribution is the complete characterization of a feedback-based, sensor-informed application for process monitoring and fabrication data acquisition and analysis. The proposed AM method is verified through the fabrication of a large-scale demonstrator. The main finding is that implementing AM in construction through cyber-physical robotic coreless FW leads to more autonomous prefabrication processes and unlocks upscaling potential. Overall, we conclude that material-system-aware communication and control are essential for the efficient automation and design of fiber-reinforced polymers in future construction.
... Fiber rovings were wound between grooves in the edges of a modular metallic winding tool. The technology was geared towards placing G/CFRP along digitally designed and structurally evaluated loadbearing paths [44,45]. ...
Novel fabrication methods are necessary to capitalize on the high strength-to-weight ratio of composites engineered for construction applications. This paper presents prefabrication strategies for geometrically-complex building elements wound out of Glass and Carbon Fiber Reinforced Polymers (G/CFRP). The research focuses on Robotic Coreless Filament Winding (RCFW), a technology that eliminates formwork, proposing upscaling and industrialization strategies combined with updated robot programming and control methods. Our application addresses the prefabrication of hyperboloid, tubular components with differentiated geometry and fiber layout. We examine how the proposed methods enabled the industrial prefabrication of a building-scale G/CFRP dome structure and discuss the industrial process relative to key fabrication parameters. Highlighting the interdisciplinary nature of the research, we envisage future directions and applications for RCFW in construction. Overall, we find that synergy between academia and industry is essential to meeting research, productivity, and certification goals in the rather conservative building industry.
... The CAD-to-CAE exchange for spatial free-form timber plates was first introduced by the Institute for Computational Design [1] and the Institute of Building Structures and Structural Design [2]. In particular, Li and Knippers [3], Krieg et al. [4], and La Magna et al. [5] developed CAD-to-FE exchange tools to simulate the behavior of segmented timber plate shells. The CAD model, which is constructed in Rhinoceros 3D [6] ...
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The current study uses knowledge from digital architecture, computer science, engineering informatics, and structural engineering to formulate an algorithmic framework for integrated Computer-Aided Design (CAD) and Computer-Aided Engineering (CAE) of Integrally-Attached Timber Plate (IATP) structures. The algorithm is designed to take the CAD 3D geometry of an IATP structure as input and automates the construction and analysis of the corresponding CAE model using a macroscopic element, which is an alternative to continuum Finite Element (FE) models. Each component of the macro model is assigned a unique tag that is linked to the relevant geometric and structural parameters. The CAE model integrity is maintained through the use of the common data model (CDM) concept and object-oriented programming. The relevant algorithms are implemented in Rhinoceros 3D using RhinoCommon, a .NET software development kit. Once the CAE macro model is generated, it is introduced to the OpenSees computational platform for structural analysis. The algorithmic framework is demonstrated using two case structures: a prefabricated timber beam with standard geometry and a free-form timber plate arch. The results are verified with measurements from physical experiments and FE models, where the time needed to convert thousands of CAD assemblies to the corresponding CAE models for response simulation is considerably reduced.
Computer-numerical-control (CNC) fabrication of interlocking-plate timber structures is a promising form of construction for housing with the potential to be socially, economically and environmentally sustainable. The primary mechanisms of load transfer in these structures rely on direct contact and friction between interlocking elements, without the nails and screws used in conventional timber structures. The development of these connections is relatively new, and therefore the application of interlocking plates structural systems in real projects is so far limited. In this study, the WikiHouse interlocking-plate timber structural system for digitally fabricated houses is presented from a design and fabrication point of view. The main structural elements of the system, the beams and columns, are hollow section members fabricated using computer-numerical-control (CNC) cut plywood panels. In the first part of the paper, the concept of Wikihouse and its fabrication process are presented. Then, the performance of the structural beams is investigated by means of experimental testing on full scale 5 m specimens. Finally, an analytical model to calculate the beam capacity and displacements is derived based on elastic beam bending and joint flexibility. Results show that the specimens failed in a ductile manner. Furthermore, it was found that the joints between the panels introduce extra flexibility to element, and that rigid-body rotations occurring in the joints within the span make a substantial contribution to the overall deflection.
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In a brief review of aspects of biology relevant to architectural design, a number of biological organisms are considered, delivering design ideas for the improvement of tree structures in the Sagrada Familia; better insulation (ideas from penguin feathers and birds’ nests) and cooling of buildings in a hot climate; light but stiff floor plates (derived from the morphology of cuttlebone); supply of fluid through a branching system of pipes and a better fire extinguisher using ideas from the spray mechanism of the bombardier beetle.
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Sea urchin skeletons are strengthened by flex- ible collagenous ligaments that bind together rigid calcite plates at sutures. Whole skeletons without ligaments (re- moved by bleaching) broke at lower apically applied forces than did intact, fresh skeletons. In addition, in three-point bending tests on excised plate combinations, sutural liga- ments strengthened sutures but not plates. The degree of sutural strengthening by ligaments depended on sutural position; in tensile tests, ambital and adapical sutures were strengthened more than adoral sutures. Adapical sutures, which grow fastest, were also the loosest, suggesting that strengthening by ligaments is associated with growth. In fed, growing urchins, sutures overall were looser than in unfed urchins. Looseness was demonstrated visually and by vibration analysis: bleached skeletons of unfed urchins rang at characteristic frequencies, indicating that sound traveled across tightly fitting sutures; skeletons of fed ur- chins damped vibrations, indicating loss of vibrational en- ergy across looser sutures. Furthermore, bleached skeletons of fed urchins broke at lower apically applied forces than bleached skeletons of unfed urchins, indicating that the sutures of fed urchins had been held together relatively loosely by sutural ligaments. Thus, the apparently rigid dome-like skeleton of urchins sometimes transforms into a flexible, jointed membrane as sutures loosen and become flexible during growth.
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This paper will focus on how the emerging scientific discipline of biomimetics can bring new insights into the field of architecture. An analysis of both architectural and biological methodologies will show important aspects connecting these two. The foundation of this paper is a case study of convertible structures based on elastic plant movements.
This paper analyzes an aberrant group of echinoids in terms of constructional morphology, i.e., as modification of an established “Bauplan” by a set of new functional and morphogenetic constraints and possibilities. The characteristics of sand dollars (flat test, spine differentiation, branched food grooves, lunules) are related to a particular combination of burrowing and sieve feeding in sandy sediments. It has independently evolved from less specialized Clypeasteroids in at least three lineages (Scutellina, Rotulidae, Arachnoididae), which have solved inherent problems differently (sutural interlocking; growth patterning of food grooves and canal systems; lunule formation; weight belts). These three groups have radiated in different degrees due to their different palegeographic histories.
If one is looking for an example of a conceptual design which is extremely appropriate in its morphology, well adapted to the surroundings, structurally and functionally optimised, and has a refined and appropriate appearance - all in one single configuration - you have either an exceptional and rare piece of fine architecture - or a common organism in Nature. That is why Nature makes an excellent object for architectural students to study structures from a conceptual and a morphological point of view. And that is why Nature - who has developed her structural systems by trial-and-error through millions of years - acts as an excellent teacher of these topics. At the same time, the idiom of Nature seems to possess a considerable attraction for students and is able to convey inspiration and imagination to the creative process of shaping architectural structures. In our surrounding living and non-living nature a number of striking statical and kinematical peculiarities have been observed. The paper will try to isolate and describe some of these observations and their relation to our engineered structures based on human thinking. The paper will deal with basic aspects as geometry, topology, redundancy and kinematic stability of structures in Nature and in architecture.
Following in the footsteps of more progressive industries, digital fabrication in architecture is on the brink of shifting from task-specific computer numerically controlled (CNC) machines to more generic industrial robots. The change from machine hardware and control software developed to facilitate a specific fabrication process towards more open-ended and generic fabrication devices enables architects to design custom fabrication processes and machine-control protocols. Achim Menges and Tobias Schwinn present how these advanced machine capabilities expand the interface between design computation and physical materialisation. Copyright © 2012 John Wiley & Sons, Ltd.
Julian Vincent, Professor of Biomimetics and Director of the Centre for Biomimetics and Natural Technologies within the Department of Mechanical Engineering at the University of Bath, identifies three distinct levels at which patterns can be translated from biology to architecture. Emphasising the importance of pattern recognition in the transfer of the most abstract derivations, he demonstrates that the greatest potential for biomimetics lies in its application for problem solving rather than straightforward mimicry of biological shapes and forms. Copyright © 2009 John Wiley & Sons, Ltd.
The last few years have witnessed a robotic revival with a reinvigoration of interest in what the robot can offer the construction industry. Martin Bechthold looks back at the first robotic boom during the 1980s and 1990s when millions of Japanese yen were invested in developing robots that could address the shortage of construction labour. Bechthold further explores the similarities and dissimilarities of the current and previous periods of activity, as supported by his research at Harvard's Graduate School of Design (GSD). Copyright © 2010 John Wiley & Sons, Ltd.
Design computation has profound impact on architectural design methods. This paper explains how computational design enables the development of biomimetic design processes specific to architecture, and how they need to be significantly different from established biomimetic processes in engineering disciplines. The paper first explains the fundamental difference between computer-aided and computational design in architecture, as the understanding of this distinction is of critical importance for the research presented. Thereafter, the conceptual relation and possible transfer of principles from natural morphogenesis to design computation are introduced and the related developments of generative, feature-based, constraint-based, process-based and feedback-based computational design methods are presented. This morphogenetic design research is then related to exploratory evolutionary computation, followed by the presentation of two case studies focusing on the exemplary development of spatial envelope morphologies and urban block morphologies.