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Research and Teaching Felix Raspall

Research and Teaching Felix Raspall Design Research 01

Design Research 02

Innovative Brick Structures


Catenary Structures


Michelle Addington [YSOA] William Martin [YSOA]

Design Research 03

Gemini. Customizable Lounge

Rowley & Newton [YSOA]

Design Research 04


Yacare. 2D 3D Chaise-Lounge


Peter de Bretteville [YSOA]

Sergio Forster [UCB]

Virtual Markets


Design Research 06

Digital Craft and Design

Suter & Jacobson [YSOA]


Design Research 07

Scripting Form and Material

Kevin Rotheroe [YSOA]


Design Research 08

Surface Tectonics


Ben Pell [YSOA]

Design Research 05

Design Research 09

H Car. Light Body Fabrication


John Eberhart [YSOA]

Evans & deSchiller [UBA]

Research at UBA


Teaching Work 01

Teaching at UBA


Research Work 01

Friedman, Forster & Ibarborde [UBA]

Design Research 01

Innovative Brick Structures Video: Yale School of Architecture. Fall 2010 Advisor. Michelle Addington with Mark Gage Project Involvement. Individual Project Abstract Masonry, broadly understood as construction by assembly of modular components, seems to have unlimited possibilities in the era of digital design and fabrication. However, are contemporary practices being able to fully realize these latent capacities? Current explorations on this field, for the most part, research on scripting and robotics to achieve complex forms and textures, but they rarely exceed the load-bearing wall typology. This research attempts a novel approach to digital design and fabrication for masonry connecting two of the most significant milestones in the development of this building technique: the work of Guastavino, who fostered the technique of lightweight vaulting built without centering, and the innovations of Dieste, who mastered reinforced masonry, in which steel reinforcement allows the realization of thin-shell structures. The research also questions the generalized ambition for a complete robotization of the fabrication process (and the elimination of hand-labor), looking for an efficient interaction of precision from digital tools with tolerance-handling and error correction from human labor.

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Digital Fabrication and Masonry 1a. Digital Fabrication for Masonry:

1b. Towards Augmented Hand-Labor:

Prevailing approach to digital fabrication for masonry focuses on the achievement of maximum precision by using robotic equipment. Hand labor and irregular materials are frequently seen as hard to compute and therefore relegated or replaced.

Since its origins, the success of masonry relies on the skills of masons to manage irregularities of materials and tolerances in the placement of the units. This research acknowledges the merits of these skills and aims to preserve and expand them by integrating digital tools with human labor rather than replacing the one for the other. Through a fabrication experiment, the use of a robotic arm was tested as an aiding tool for the mason, pointing the precise location and orientation of units while providing temporary support. In future experiments, 3D surveying tools can be tested as an adequate alternative for the location of masonry units.

Image: Robotization of masonry as replacement of hand-labor is well represented in the paper by Pritschow, Dalacker, Kurz and Gaenssleb. Technological aspects in the development of a mobile bricklaying robot (1996). Research and Teaching 4

Image: The proposed augmented hand labor, in which mason deals with the binding of the units, while the robot provides support and general location.

Structural and Fabrication Innovation 2a. Innovation in Masonry

2b. Self-Supporting Shell Fabrication

Catalan Vault:

Reinforced Masonry Shells:

An important advantage of Catalan vault is that its fabrication requires minimum formwork and it can be done without centering. Each row supports itself and serves as support for the following one.

The use of steel reinforcement in masonry construction extends its traditional boundaries into the realm of thin-shell structures, enormously increasing its material performance, as well as its formal and expressive possibilities.

This research proposes a fabrication and structural method in which shell structure fabrication can support itself during the assembly process. For the limitations of this research, this method is proposed theoretically and tested in two physical experiment. However, future research will require precise structural study.

Shell Structure: resistance by form. Guastavino: surveying device for the dome of St. John Divine, built without centering Ochsendorf: Soil Cement Vaults in South Africa.

Dieste: Reinforced Masonry. Gaussian Vault.

Physical experiment 1. Assembly test using fast drying mortar and steel reinforcement.

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Experiment 3a. Coding for modularization of surfaces.

3b. Application in a cantilever structure

3c. Determining Points and Vectors in space.

First, a script to array masonry units along a base surface was written. It can handle different types of bond, as well as vary the geometry, size, rotation and separation of the units.

A double-curved surface, designed to resist the cantilever stress, was panelized using this script (3a).

For each masonry unit, the script determines location and orientation, creating an excel spreadsheet that contains unit id#, coordinates and normal vector (orientation).

Screenshot. Script applied to the base surface.

Screenshot. Script exporting coordinates and vectors.

Physical Experiment 2. Assembly sequence

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Assembly and Results 3d. Translation into the robotic arm language.

4. Final Assembly integrating Robotic Arm and Hand Labor

Coordinates and normal vectors in this spreadsheet area translated to the specific input language of the robot (using local coordinate systems and quaternion angles).

The assembly sequence was successfully tested using EPS modules and synthetic string as reinforcement. Future research will test this method using more durable and heavier materials, as well as the use of alternative surveying devices (1b).

//////// SETTINGS ToolChange(1,1) SetRPM(20000 PPRINT/ Toolpath Name: BACKfinish01 PPRINT/ Output:

choose tool starts spindle PPRINT/ Units: MM

//////// MOVEMENT $VEL.CP=0.1666 PPRINT/ MoveType: 01 LIN {X 393.1622,Y 9.99993,Z 384.25854,I 0.0,J 1.,K 0.0} C_Dis LIN {X 549.90369,Y 9.99993,Z 652.25854,I 0.0,J 1.,K 0.0} C_Dis LIN {X 549.90369,Y 4.99993,Z 652.25854,I 0.0,J 1.,K 0.0} C_Dis

speed movetype ??? move endmill

Screenshot. Data input in the Robot Interface.

EPS unit, with slit for reinforcement.

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Design Research 02

Digital Catenary Yale School of Architecture. Spring 2009 [exhibited at Yale Digital Media Show 09-10] Instructor. William Martin Project Involvement. Individual Project Abstract This project develops a digital tool for the design of catenary structures, which allows the creation and modification of 3D networks with realtime simulation of its behavior under gravity. A key feature of this tool is the user-friendly and intuitive interface, which overlays the plan -for creation and modification- with a 3D-orbitable perspective view -for immediate verification of the results. Additionally, DXF and PDF export allow further development for 3D refinement, structural simulation or rapid prototyping. This tool was programmed using Processing language; it employs a particle system physics engine to simulate gravity and a 3D visualization library.

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Inputs 1. Network of Nodes and Connections. Users design 3D networks by creating or modifying nodes and by establishing connections between them. Nodes can be fixed, acting as support, or can be free, serving as bifurcation points. The behavior of networks under the force of gravity is calculated on real-time. While users are creating or modifying the network, a 3D view of the structure can be activated. This allows them to understand the threedimensional effects of their design decisions, to increase their capacity to make variations and verification quickly, and therefore, to gain major control over their projects.

screenshot. Help

The orbitable 3D view, updated in real-time

Screenshot. Overlaid plan (grayscale) and perspective (red). Users can simultaneously edit the plan (dragging nodes for example) and orbit the perspective. This real-time verification augments designers’ control over their projects. Research and Teaching 10

Plan Input: Black nodes represent the fixed points -supports- and gray nodes, -free points that move under gravity-. Lines represent connections between nodes (variable thickness indicating the stress in that connection).

Outputs 2. DXF and PDF This tool includes exporting feature, in both *.dxf 3D vector format and *.pdf 2D vector format. Exported files can be easily 3D prototyped by simply thickening the linework or can be further edited to create more elaborated sections.

Below. Physical model easily created directly using rapid prototyping machines. Right. Rhino 3D Model, giving variable thickness to the connection lines.

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Code 3a. Main features:

3b. Processing Object Oriented Programming Language

- Several modes of creation and transformation of the network. - 2D and 3D visualization (simultaneous or separate) - Overlay of technical drawing as background reference - 2D (pdf) and 3D (dxf) export.

The code for this design tool was written using Processing Object Oriented Programming Language. It uses the Traer Physics library and the Peasy Cam library.



void mousePressed(){ if (mode == 1) { // DRAG NODES for( int i=0; i<physics.numberOfParticles(); i++ ){ Particle p = physics.getParticle( i ); if( dist( p.position().x(), p.position().y(), mouseX, mouseY ) < NODE_SIZE ){ draggingNode = p; return; // cam.setMouseControlled(false); }}} if (mode == 2) { // CREATE - ERASE NODE for( int i=0; i<physics.numberOfParticles(); i++ ){ Particle p = physics.getParticle( i ); if( dist( p.position().x(), p.position().y(), mouseX, mouseY ) < NODE_SIZE ) { eraseParticle(p); return; }} addNode (); } if (mode == 3) { // FIX - UNFIXNODES for( int i=0; i<physics.numberOfParticles(); i++ ){ Particle p = physics.getParticle( i ); if( dist( p.position().x(), p.position().y(), mouseX, mouseY ) < NODE_SIZE ){ if (p.isFree()) p.makeFixed(); else p.makeFree(); return; }}} if (mode == 4) { // CREATE CONNECTIONS for( int i=0; i<physics.numberOfParticles(); i++ ){ Particle p = physics.getParticle( i ); if( dist( p.position().x(), p.position().y(), mouseX, mouseY ) < NODE_SIZE ){ if (connectA == null) connectA = p; else { if (connectA != p) { makeEdgeBetween(connectA, p ); connectA = null; } }

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Appendix. Preliminary programming 4a. Connecting dots

4b. 3D Structures

Tool that generates 2D network of moving nodes by evaluating proximity of the nodes and their number of connections.

Tool that creates 3D structures from nodes that self adjusts to achieve stability and strong interconnectivity. Nodes with fewer number of links move until they find more connected condition.

float[] x1 = new float[50]; float[] y1 = new float[50]; float[] numberconnect = new float[50]; void setup() { size(700, 400, OPENGL); colorMode (HSB); background(80, 200, 10); frameRate(20); } void draw() { background(80, 200, 10);

int numberNodes = 50; float[] x1 = new float[numberNodes]; float[] y1 = new float[numberNodes]; float[] z1 = new float[numberNodes]; float[] numberconnect = new float[numberNodes]; float[] energy = new float [numberNodes]; float [] speed = new float [numberNodes]; float initDispersion = 50; float connectDist = 25; import peasy.*; PeasyCam cam;

// RANDOMIZE POINTS THE FIRST FRAME if (frameCount == 1) { print (frameCount); for (int i = 0; i < x1.length; i = i+1) { x1 [i] = random (700); y1 [i] = random (400);

void setup() { size(700,400,OPENGL); cam = new PeasyCam(this, 100); cam.setMinimumDistance(50); cam.setMaximumDistance(500); frameRate (15);

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Design Research 03

Gemini. Customizable Lounge. Yale School of Architecture. Spring 2009 [published in Yale Retrospecta 2009-2010, exhibited in ICFF 2010 New York and Yale Digital Media Show 09-10] Instructors. Joshua Rowley and Timothy Newton Project Involvement. Individual Project Abstract This project explores a possible approach to mass-customization for free-form furniture design. It develops a form-making and fabrication method and tests its feasibility through the design of a lounge system. On a first stage, form-generation is systematized by organizing customizable variables and the way in which they inform the piece of furniture. Secondly, it proposes a CNC fabrication method that reduces the waste typically involved in free-form fabrication by subtractive procedures. The proposed â&#x20AC;&#x2DC;additive-subtractive methodâ&#x20AC;&#x2122;, works additively for the larger scale and subtractively for the finishing. A full scale double-chair was developed and fabricated to test feasibility and limitations of this method.

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Form-Generation 1. Form Generator: Polygon Strings.

2. Smoothing and Adjusting Polygon Strings.

In order to control the customization of free-form objects, a strict topological logic defined the threshold of variation for this lounge system. At the bigger scale, strings of polygon organize the global layout in a wide yet limited catalog of configurations.

2D Polygon Strings are extruded to create prisms. Where backs are needed, vertex are pulled up. The resulting polyhedrical shape is smoothed using the T-Splines modeler for Rhino.

Base configuration

Sit orientation


As the main case study of the project, the octagon+hexagon string was developed through the fabrication phase.



Vertex up Back

Vertex up Back



Blended geometry N Original geometry

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Additive-Subtractive Assembly Method




5 9


33 21 30

First, flat material is CNC cut and piled to get a stepped version of the desired shape.



11 48


Accurate position of the pieces is achieved by alignment holes that are knitted with wood dowels. The pieces are glued together to form a solid block.












The Additive-Subtractive Method works in two steps, first by piling layers of flat material, and second, by smoothing the stepped profile caused by the material stacking.

3. Additive Phase:


This project proposes a CNC construction method feasible for the fabrication of large free-form prototypes, which reduces the amount of waste and milling time needed in typical subtractive methods.



12 7





Kit of parts. Plywood pieces and alignment dowels. 20




24 19











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Assembly Method (cont) 4. Subtractive Phase: Secondly, a CNC mill smooths the stepped profile into the desired free-form shape. Due to the formal complexity of the case-study , a 7-axis CNC mill was needed to reach the underside. A key factor to optimize this process is an accurate definition of tolerances margin between the finished surface and the piled stock block. In this exercise, 1/2â&#x20AC;? proved to be excessive, as 1/4â&#x20AC;? would have been enough.

Below. 5-axis robotic and stock material

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Results 4. Functionality

5. Material Efficiency

During the initial stages of this project, a full scale form prototype was fabricated in EPS to test ergonomics and possible conflicts with the milling process.

Use of material was quantified to verify efficiency rates. A total of 8870 cu in of plywood was used for the prototype. The finished model’s volume was 3540 cu in (efficiency: 40%).

The final prototype was tested by multiple users with positive reaction to its ergonomic and structural performance.

More than half of the waste happened in the additive phase. This value can be reduced by better nesting the pieces, feasible in larger production.

Raw material:

2.75 4x8’ sheets of 3/4” Plywood 8870 cu in

The amount of waste in the subtractive phase can be reduced by adjusting tolerances, which proved excessive in this prototype.

Below. First prototype in EPS reinforced with Urethane, to test ergonomics.

Stacked stock material: 5677 cu in (64%)

Finished Prototype: 3540 cu in (40%)

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Design Research 04

Yacare. 2D 3D Chaise Lounge Yale School of Architecture. Spring 2009 [published in Yale Retrospecta 2008-2009, Exhibited at Yale Digital Media Show 10-11] Instructor. Peter deBreteville Project Involvement. Individual Project Abstract Yacare chaise-lounge explores means to efficiently create 3D objects using 2D materials. Two basic operations convert flat surface into volume: bending and folding. Correspondingly, two materials are studied: laminated wood and mild steel. These two operations and materials were tested through the design of a chaise-lounge. The expression of the final design seeks to exposes the dualities hard/ soft (metal-wood) and faceted/smooth (bended-folded), creating a dialogue between the exterior structural surface and the interior layer, in contact with the human body. The simple segmented topology and the integration of CNC tools in this design makes it reasonable for mass-customization.

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Concept 1. Two materials, two operations

2. Variable section, consistent topology

Folding Steel: Exterior, structure. Bending Wood: Interior, interface with human body.

Each of the eight segments of the chair responds to the same topological logic. Middle segments generate the legs; extreme segments, the cantilevered back and leg rest.

1 2 laminated wood

8 7

3 4

central spine

folded steel

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6 5

Assembly 3a. Folding Steel One and a half sheets of 18 Gage steel were cut with plasma cutter. Dashed lines aided the bending process and tabs facilitated the welding.

1 2 3






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Assembly (cont)


3b. Bending Wood

4. Final prototype.

Pieces on bending poplar were CNC cut and Mahogany veneer, laser cut. They were laminated in vacuum bag to achieve the curved form.

According to users, final prototypeâ&#x20AC;&#x2122;s ergonomics are very comfortable. Welding and bending processes require further optimization.









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Design Research 05

Virtual Markets Bolivian Catholic University, Architectural Association, UBA, 2003 [Exhibited at La Paz City Hall Exhibition Center, 2003] Project Involvement. Collaborative Project with F Papandrea, D Kayser Program. Organization System for Street-Markets Location. La Paz, Bolivia Abstract This project proposes and develops a design workflow that interweaves different software packages with the objective of simulating self-organizing systems. It attempts to decode and reproduce the complexity of the street markets in the city of La Paz, Bolivia. The core of the project integrates excel data processing with AutoCad 3D modeling in a feedback loop that makes the form generation process non-linear and evolutive. The design starts with a survey of relevant variables in the street markets, such as booth dimensions, distribution and flow patterns. Then, it simulates self organization of circulation and selling areas. The final stage involves material determination of the different parts of the project.

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Workflow Self Organizing Structures In the street markets of La Paz, the organization of each booth only responds to local conditions, as no higher control agent exists. Surprisingly, these markets as a whole achieve a global coherence that emerges exclusively from these local decisions. This project attempts to develop a digital workflow capable of reproducing these self-organizing systems. For this purpose, local decision-making is simulated using excel spreadsheets, which create AutoCad commands. Autocad 3D models are audited and this information is reintroduced again in Excel in an iterative process.



Information - Material Actualization

PHYSICAL MODEL Material capacities constraints

SPREADSHEET Data analysis Infrastructure determination

Information - Material Actualization



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VIRTUAL MODEL Virtual capacities constraints

Information 1. Information Matrix The first step is the construction of a data matrix that includes relevant variables from city markets. Existing structures as well as distribution of fluxes are incorporated into spreadsheets, which analyze and optimize land use, circulation efficiency and infrastructure distribution.

2. Material Analysis Concurrently, a generic prototype for commercial stalls and circulation paths is designed, reusing simple building practices from existing markets.

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Material Organization 3. Algorithm

4. Design Refinement

Data from the information matrix (1) and geometry from the material analysis (2), are actualized to produce the commands for 3D modeling. The emergent model is refined through a digital iterative process.

A sector is further developed, determining specific location and dimensions of structural posts, roofs membranes, selling surfaces and sanitary services.


Roofs topography

Water draining

Binding points

Exhibition surface


Topographic mesh

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Roofs Topography

Props Roofs topography Exhibition Surface

Infrastructure Props Topographic Mesh

Roof plan Binding points


Border conditions

Topographic mesh

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Design Research 06

Digital Craft and Design Yale School of Architecture. Spring 2009 [published in Yale Retrospecta 2008-2009] Instructors. John Jacobson and Lindsay Suter Project Involvement. Individual Project Program. Herb-mill. Description This design exercise proposes a form-making and fabrication sequence that interweaves hand-modeling with digital fabrication for product design applications. Tested for the design of a herb-mill, this sequence includes clay modeling, 3D point cloud scanning, 3D refinement and CNC fabrication and assembly.



1. Clay Model

2. 3D scanning

3. 3D modeling and engineering

4. Final Prototype

Fluid forms are handcrafted in clay, taking advantage of direct tactile and visual control of the form.

Point-cloud scanning generates precise reading of the physical model, including irregularities achieved by handwork.

The point cloud model is rationalized and engineered to host the mechanism of the mill.

The final prototype was CNC milled in hardwood. For larger productions, plastic or aluminum injection are more suitable techniques.

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Design Research 07

Scripting Form and Material Yale School of Architecture. Spring 2009 Instructor. Kevin Rotheroe Project Involvement. Individual Project Description This research develops scripting for the manipulation of NURBs surfaces and proposes two fabrication strategies: Triangular folding and surface thickening. It also studies interactions between these two strategies. Series of scripting and material experiments test, in a systematic way, formal and material opportunities for these scripts.

Material Test. Folding and Thickening operations integrated.

Material Test. ABS plastic

Surface Operators 1. Surface Thickening.

2. Triangular Folding.

This set of surface controllers are designed to modify an initial surface by adding thickness, noise, apertures, creases and channels.

This script creates a folded triangular structure, allowing variation on the thickness of the structure and density of the folds.

Script. Surface thickening operators.



Script. Surface Folding Operator Script. Folding and Thickening operations integrated.



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Design Research 08

Surface Tectonics Yale School of Architecture. Spring 2010 [published in Yale Retrospecta 2009-2010] Instructor. Ben Pell Project Involvement. Collaborative Project with G Yang Program. Storefront for Jewelry Description This project mediates between the logic of surface and the tectonics of masonry by interweaving block piling techniques with curvilinear geometries. As a case study, a storefront was designed. Curvature, articulation and thickness of exhibition surfaces address the perceptual requirements of a typical storefront, in which skewed projections to pedestrians are more relevant than the traditional frontality of the facade. Requirements of product exhibition, views to the inside and structural soundness modify an initially uniform triangulation and depth into a singular storefront. A full-scale prototype was built using customized masonry units made out of folded metal and assembled with magnets.

Approach from left

Approach from right

Concept 1. Fabrication technique.

2. Surface Parameters.

3. Unit Determination

Fabrication of each unique unit was simplified to only three folds (pre-scored). Assembly using magnets was extremely fast.

Orientation and depth of the storefront are controlled by the direction of the pedestrian flow, as well as light, visibility, exhibition and structural requirements.

Individual units are customized to accommodate different program (exhibition, opaque and transparent enclosure), and to host geometrical operations (boolean, offset) Triangulation



Depth Boolean union

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Design Research 09

H Car. Light Body Fabrication Yale School of Architecture. Fall 2008 [selected through competition and built] Instructor. John Eberhart Project Involvement. Collaborative Project with N Gilliland, F Singer and A Vittadini Description This project explores a free-form fabrication method for the body of Yaleâ&#x20AC;&#x2122;s hybrid car. It aimed to create a dynamic form suitable for the experimental race car by the School of Engineering, which required minimum weight. The design reviews airplane-model fabrication methods, proposing fiberglass-reinforced foam wings that hinges from the carâ&#x20AC;&#x2122;s chassi. It was selected through competition and built (full-scale) using EPS reinforced with fiberglass.



1. Light Free-form Body

2. Reinforced EPS

The main requirement was an image that expresses dynamism and speed. The main constraint was weight limitation. This design responded with two very light wings.

Use of reinforced EPS allowed easy milling of the free-form body and minimized the weight. Reinforcement with fiberglass provided adequate strength EPS Core

Fiberglass Steel Insert and hinge

Above: detail model. Below: Study model. Right: Fabrication

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Research Work 01

Research at UBA University of Buenos Aires, 2003-2007 Description As a member of the Habitat and Energy Research Center, I conducted research on material and energy optimization for building envelopes. My work specialized in the development of digital workflows for the design and evaluation of facade systems, and it was published and presented in congresses in Latin America. Additionally, I took part in more than 30 consultancy projects in which these methods were applied to real projects. The following four pages show drawings, graphics, models and schemes of my production for consultancy projects, including Norman Fosterâ&#x20AC;&#x2122;s Aleph Housing in Buenos Aires, the International Ferry terminal in Buenos Aires and the Headquarters for Aerolineas Argentina Airlines.

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Teaching Work 01

Teaching at UBA University of Buenos Aires, 2003-2007 Courses Design Studio, Third year. Instructor (2008). Theory of Architecture. Instructor (2003-2008) Morphology II. Teaching Assistant (2001-2002) Description As a teacher both of studio and non-studio courses, I aimed to provide the students with a research perspective of design and promoted the exploration with digital tools for experimental design processes.

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Theory of Architecture Course The Theory of Architecture course at UBA proposes an understanding of design as investigation practice to students. Learning contemporary theories, discourses and techniques, students are required to take a position and develop an experimental design project consistent with their stance. On this and the next spreads, the syllabus I proposed for the 2006 Summer Course and projects by students.

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Written Material and Software Tutorials As part of my teaching activities, I developed original material for students, which served as introduction to digital architecture, scripting techniques, form generation processes and possible applications in architectural design. On the right: Example of a tutorial on MaxScript.

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Felix Raspall

Research Projects  
Research Projects  

Research Projects