Essential techniques for laparoscopic surgery simulation

Laparoscopic surgery is a complex minimum invasive operation that requires long learning curve for the new trainees to have adequate experience to become a qualified surgeon. With the development of virtual reality technology, virtual reality-based surgery simulation is playing an increasingly important role in the surgery training. The simulation of laparoscopic surgery is challenging because it involves large non-linear soft tissue deformation, frequent surgical tool interaction and complex anatomical environment. Current researches mostly focus on very specific topics (such as deformation and collision detection) rather than a consistent and efficient framework. The direct use of the existing methods cannot achieve high visual/haptic quality and a satisfactory refreshing rate at the same time, especially for complex surgery simulation. In this paper, we proposed a set of tailored key technologies for laparoscopic surgery simulation, ranging from the simulation of soft tissues with different properties, to the interactions between surgical tools and soft tissues to the rendering of complex anatomical environment. Compared with the current methods, our tailored algorithms aimed at improving the performance from accuracy, stability and efficiency perspectives. We also abstract and design a set of intuitive parameters that can provide developers with high flexibility to develop their own simulators

Augmented reality-based visual-haptic modeling for thoracoscopic surgery training systems

Background: Compared with traditional thoracotomy, video-assisted thoracoscopic surgery (VATS) has less minor trauma, faster recovery, higher patient compliance, but higher requirements for surgeons. Virtual surgery training simulation systems are important and have been widely used in Europe and America. Augmented reality (AR) in surgical training simulation systems significantly improve the training effect of virtual surgical training, although AR technology is still in its initial stage. Mixed reality has gained increased attention in technology-driven modern medicine but has yet to be used in everyday practice. Methods: This study proposed an immersive AR lobectomy within a thoracoscope surgery training system, using visual and haptic modeling to study the potential benefits of this critical technology. The content included immersive AR visual rendering, based on the cluster-based extended position-based dynamics algorithm of soft tissue physical modeling. Furthermore, we designed an AR haptic rendering systems, whose model architecture consisted of multi-touch interaction points, including kinesthetic and pressure-sensitive points. Finally, based on the above theoretical research, we developed an AR interactive VATS surgical training platform. Results: Twenty-four volunteers were recruited from the First People's Hospital of Yunnan Province to evaluate the VATS training system. Face, content, and construct validation methods were used to assess the tactile sense, visual sense, scene authenticity, and simulator performance. Conclusions: The results of our construction validation demonstrate that the simulator is useful in improving novice and surgical skills that can be retained after a certain period of time. The video-assisted thoracoscopic system based on AR developed in this study is effective and can be used as a training device to assist in the development of thoracoscopic skills for novices

3D modeling of the human upper limb including the biomechanics of joints, muscles and soft tissues

The challenge in virtual human modeling is to achieve the representation of the main human characteristics with as much realism as possible. Such achievements would allow the simulation and/or analysis of many virtual situations involving humans. Simulation is especially useful to derive information from the models so as to predict and/or reproduce the behaviors that would be observed in real situations. Computer methods in visualization and simulation have thus great potential for advances in medicine. The processes of strength generation and motion coordination are some of these phenomena for which there is still much remaining to be understood. The human shoulder is also probably the articulation of the human body which deserves more than any other to be named "terra incognita". Investigations towards the biomechanical modeling and simulation of the human upper limb are therefore presented in this study. It includes thorough investigation into the musculoskeletal anatomy and biomechanics of the human upper limb, into the biomechanical constitutive modeling of muscles and soft tissues, and into the nonlinear continuum mechanics and numerical methods, especially the incremental finite element methods, necessary for their simulation. On this basis, a 3-D biomechanical musculoskeletal human upper limb model has been designed using the Visible Human Data provided by the U.S. National Library of Medicine, and applied to the dynamic musculoskeletal simulation of the human upper limb. This research has been achieved in the context of the EU ESPRIT Project CHARM, whose objective has been to develop a comprehensive human animation resource database and a set of software tools allowing the modeling of the human complex musculoskeletal system and the simulation of its dynamics, including the finite element simulation of soft tissue deformation and muscular contraction. An investigation towards the application of this knowledge for the realistic modeling and animation of the upper limb in computer animation is then presented. The anatomical and biomechanical modeling of the scapulo-thoracic constraint and the shoulder joint sinus cones are proposed and applied to the realistic animation, using inverse kinematics, of a virtual skeleton and an anatomic musculoskeletal body model

Simulation Method for the Physical Deformation of a Three-Dimensional Soft Body in Augmented Reality-Based External Ventricular Drainage

Objectives Intraoperative navigation reduces the risk of major complications and increases the likelihood of optimal surgical outcomes. This paper presents an augmented reality (AR)-based simulation technique for ventriculostomy that visualizes brain deformations caused by the movements of a surgical instrument in a three-dimensional brain model. This is achieved by utilizing a position-based dynamics (PBD) physical deformation method on a preoperative brain image. Methods An infrared camera-based AR surgical environment aligns the real-world space with a virtual space and tracks the surgical instruments. For a realistic representation and reduced simulation computation load, a hybrid geometric model is employed, which combines a high-resolution mesh model and a multiresolution tetrahedron model. Collision handling is executed when a collision between the brain and surgical instrument is detected. Constraints are used to preserve the properties of the soft body and ensure stable deformation. Results The experiment was conducted once in a phantom environment and once in an actual surgical environment. The tasks of inserting the surgical instrument into the ventricle using only the navigation information presented through the smart glasses and verifying the drainage of cerebrospinal fluid were evaluated. These tasks were successfully completed, as indicated by the drainage, and the deformation simulation speed averaged 18.78 fps. Conclusions This experiment confirmed that the AR-based method for external ventricular drain surgery was beneficial to clinicians

Meshfree and Particle Methods in Biomechanics: Prospects and Challenges

The use of meshfree and particle methods in the field of bioengineering and biomechanics has significantly increased. This may be attributed to their unique abilities to overcome most of the inherent limitations of mesh-based methods in dealing with problems involving large deformation and complex geometry that are common in bioengineering and computational biomechanics in particular. This review article is intended to identify, highlight and summarize research works on topics that are of substantial interest in the field of computational biomechanics in which meshfree or particle methods have been employed for analysis, simulation or/and modeling of biological systems such as soft matters, cells, biological soft and hard tissues and organs. We also anticipate that this review will serve as a useful resource and guide to researchers who intend to extend their work into these research areas. This review article includes 333 references

Shared control for natural motion and safety in hands-on robotic surgery

Hands-on robotic surgery is where the surgeon controls the tool's motion by applying forces and torques to the robot holding the tool, allowing the robot-environment interaction to be felt though the tool itself. To further improve results, shared control strategies are used to combine the strengths of the surgeon with those of the robot. One such strategy is active constraints, which prevent motion into regions deemed unsafe or unnecessary. While research in active constraints on rigid anatomy has been well-established, limited work on dynamic active constraints (DACs) for deformable soft tissue has been performed, particularly on strategies which handle multiple sensing modalities. In addition, attaching the tool to the robot imposes the end effector dynamics onto the surgeon, reducing dexterity and increasing fatigue. Current control policies on these systems only compensate for gravity, ignoring other dynamic effects. This thesis presents several research contributions to shared control in hands-on robotic surgery, which create a more natural motion for the surgeon and expand the usage of DACs to point clouds. A novel null-space based optimization technique has been developed which minimizes the end effector friction, mass, and inertia of redundant robots, creating a more natural motion, one which is closer to the feeling of the tool unattached to the robot. By operating in the null-space, the surgeon is left in full control of the procedure. A novel DACs approach has also been developed, which operates on point clouds. This allows its application to various sensing technologies, such as 3D cameras or CT scans and, therefore, various surgeries. Experimental validation in point-to-point motion trials and a virtual reality ultrasound scenario demonstrate a reduction in work when maneuvering the tool and improvements in accuracy and speed when performing virtual ultrasound scans. Overall, the results suggest that these techniques could increase the ease of use for the surgeon and improve patient safety.Open Acces

Haptics-based Modeling and Simulation of Micro-Implants Surgery

Ph.DDOCTOR OF PHILOSOPH

Curve Skeleton and Moments of Area Supported Beam Parametrization in Multi-Objective Compliance Structural Optimization

This work addresses the end-to-end virtual automation of structural optimization up to the derivation of a parametric geometry model that can be used for application areas such as additive manufacturing or the verification of the structural optimization result with the finite element method. A holistic design in structural optimization can be achieved with the weighted sum method, which can be automatically parameterized with curve skeletonization and cross-section regression to virtually verify the result and control the local size for additive manufacturing. is investigated in general. In this paper, a holistic design is understood as a design that considers various compliances as an objective function. This parameterization uses the automated determination of beam parameters by so-called curve skeletonization with subsequent cross-section shape parameter estimation based on moments of area, especially for multi-objective optimized shapes. An essential contribution is the linking of the parameterization with the results of the structural optimization, e.g., to include properties such as boundary conditions, load conditions, sensitivities or even density variables in the curve skeleton parameterization. The parameterization focuses on guiding the skeletonization based on the information provided by the optimization and the finite element model. In addition, the cross-section detection considers circular, elliptical, and tensor product spline cross-sections that can be applied to various shape descriptors such as convolutional surfaces, subdivision surfaces, or constructive solid geometry. The shape parameters of these cross-sections are estimated using stiffness distributions, moments of area of 2D images, and convolutional neural networks with a tailored loss function to moments of area. Each final geometry is designed by extruding the cross-section along the appropriate curve segment of the beam and joining it to other beams by using only unification operations. The focus of multi-objective structural optimization considering 1D, 2D and 3D elements is on cases that can be modeled using equations by the Poisson equation and linear elasticity. This enables the development of designs in application areas such as thermal conduction, electrostatics, magnetostatics, potential flow, linear elasticity and diffusion, which can be optimized in combination or individually. Due to the simplicity of the cases defined by the Poisson equation, no experts are required, so that many conceptual designs can be generated and reconstructed by ordinary users with little effort. Specifically for 1D elements, a element stiffness matrices for tensor product spline cross-sections are derived, which can be used to optimize a variety of lattice structures and automatically convert them into free-form surfaces. For 2D elements, non-local trigonometric interpolation functions are used, which should significantly increase interpretability of the density distribution. To further improve the optimization, a parameter-free mesh deformation is embedded so that the compliances can be further reduced by locally shifting the node positions. Finally, the proposed end-to-end optimization and parameterization is applied to verify a linear elasto-static optimization result for and to satisfy local size constraint for the manufacturing with selective laser melting of a heat transfer optimization result for a heat sink of a CPU. For the elasto-static case, the parameterization is adjusted until a certain criterion (displacement) is satisfied, while for the heat transfer case, the manufacturing constraints are satisfied by automatically changing the local size with the proposed parameterization. This heat sink is then manufactured without manual adjustment and experimentally validated to limit the temperature of a CPU to a certain level.:TABLE OF CONTENT III I LIST OF ABBREVIATIONS V II LIST OF SYMBOLS V III LIST OF FIGURES XIII IV LIST OF TABLES XVIII 1. INTRODUCTION 1 1.1 RESEARCH DESIGN AND MOTIVATION 6 1.2 RESEARCH THESES AND CHAPTER OVERVIEW 9 2. PRELIMINARIES OF TOPOLOGY OPTIMIZATION 12 2.1 MATERIAL INTERPOLATION 16 2.2 TOPOLOGY OPTIMIZATION WITH PARAMETER-FREE SHAPE OPTIMIZATION 17 2.3 MULTI-OBJECTIVE TOPOLOGY OPTIMIZATION WITH THE WEIGHTED SUM METHOD 18 3. SIMULTANEOUS SIZE, TOPOLOGY AND PARAMETER-FREE SHAPE OPTIMIZATION OF WIREFRAMES WITH B-SPLINE CROSS-SECTIONS 21 3.1 FUNDAMENTALS IN WIREFRAME OPTIMIZATION 22 3.2 SIZE AND TOPOLOGY OPTIMIZATION WITH PERIODIC B-SPLINE CROSS-SECTIONS 27 3.3 PARAMETER-FREE SHAPE OPTIMIZATION EMBEDDED IN SIZE OPTIMIZATION 32 3.4 WEIGHTED SUM SIZE AND TOPOLOGY OPTIMIZATION 36 3.5 CROSS-SECTION COMPARISON 39 4. NON-LOCAL TRIGONOMETRIC INTERPOLATION IN TOPOLOGY OPTIMIZATION 41 4.1 FUNDAMENTALS IN MATERIAL INTERPOLATIONS 43 4.2 NON-LOCAL TRIGONOMETRIC SHAPE FUNCTIONS 45 4.3 NON-LOCAL PARAMETER-FREE SHAPE OPTIMIZATION WITH TRIGONOMETRIC SHAPE FUNCTIONS 49 4.4 NON-LOCAL AND PARAMETER-FREE MULTI-OBJECTIVE TOPOLOGY OPTIMIZATION 54 5. FUNDAMENTALS IN SKELETON GUIDED SHAPE PARAMETRIZATION IN TOPOLOGY OPTIMIZATION 58 5.1 SKELETONIZATION IN TOPOLOGY OPTIMIZATION 61 5.2 CROSS-SECTION RECOGNITION FOR IMAGES 66 5.3 SUBDIVISION SURFACES 67 5.4 CONVOLUTIONAL SURFACES WITH META BALL KERNEL 71 5.5 CONSTRUCTIVE SOLID GEOMETRY 73 6. CURVE SKELETON GUIDED BEAM PARAMETRIZATION OF TOPOLOGY OPTIMIZATION RESULTS 75 6.1 FUNDAMENTALS IN SKELETON SUPPORTED RECONSTRUCTION 76 6.2 SUBDIVISION SURFACE PARAMETRIZATION WITH PERIODIC B-SPLINE CROSS-SECTIONS 78 6.3 CURVE SKELETONIZATION TAILORED TO TOPOLOGY OPTIMIZATION WITH PRE-PROCESSING 82 6.4 SURFACE RECONSTRUCTION USING LOCAL STIFFNESS DISTRIBUTION 86 7. CROSS-SECTION SHAPE PARAMETRIZATION FOR PERIODIC B-SPLINES 96 7.1 PRELIMINARIES IN B-SPLINE CONTROL GRID ESTIMATION 97 7.2 CROSS-SECTION EXTRACTION OF 2D IMAGES 101 7.3 TENSOR SPLINE PARAMETRIZATION WITH MOMENTS OF AREA 105 7.4 B-SPLINE PARAMETRIZATION WITH MOMENTS OF AREA GUIDED CONVOLUTIONAL NEURAL NETWORK 110 8. FULLY AUTOMATED COMPLIANCE OPTIMIZATION AND CURVE-SKELETON PARAMETRIZATION FOR A CPU HEAT SINK WITH SIZE CONTROL FOR SLM 115 8.1 AUTOMATED 1D THERMAL COMPLIANCE MINIMIZATION, CONSTRAINED SURFACE RECONSTRUCTION AND ADDITIVE MANUFACTURING 118 8.2 AUTOMATED 2D THERMAL COMPLIANCE MINIMIZATION, CONSTRAINT SURFACE RECONSTRUCTION AND ADDITIVE MANUFACTURING 120 8.3 USING THE HEAT SINK PROTOTYPES COOLING A CPU 123 9. CONCLUSION 127 10. OUTLOOK 131 LITERATURE 133 APPENDIX 147 A PREVIOUS STUDIES 147 B CROSS-SECTION PROPERTIES 149 C CASE STUDIES FOR THE CROSS-SECTION PARAMETRIZATION 155 D EXPERIMENTAL SETUP 15

Diseño basado en prestaciones en la arquitectura. Estrategias proyectuales para mejorar la eficiencia energética de los edificios

En el context actual, en què l'estalvi en el consum d'energia s'ha convertit en un objectiu prioritari per a l'arquitectura, són necessaris mètodes i eines que permetin projectar amb eficàcia edificis energèticament eficients. El disseny basat en prestacions (performance-based design o PBD) és un mètode de disseny que aspira a millorar la presa de decisions durant el projecte per tal de garantir que un cop construït el edifici complirà amb els requisits preestablerts. El disseny basat en prestacions (DBP) va sorgir a partir de la Investigació Operativa (IO) i l'Anàlisi de Sistemes (AS), disciplines que es van desenvolupar durant la Segona Guerra Mundial amb la finalitat de millorar la presa de decisions en l'àmbit militar. Mitjançant el DBP es "simulaven", emprant models matemàtics i amb el suport de la tecnologia informàtica, els efectes de solucions alternatives per triar la que millor complia uns objectius determinats. La reducció d'errors en la presa de decisions va ser considerada una de les seves avantatges principals, i artefactes tecnològics com míssils i coets, i també l'ordinador, van ser els seus productes més destacats. Durant la segona meitat del segle XX, el DBP va començar a introduir-se en l'àmbit de l'arquitectura. El concepte de performance es va contraposar a la noció de funció que havia prevalgut en el discurs arquitectònic des del segle XIX, i que va constituir un dels dogmes del moviment modern. Mentre que el debat sobre la funció en l'arquitectura s'havia centrat fins llavors en el caràcter representatiu de l'edifici, és a dir, en la capacitat de la forma per expressar la funció en termes estètics, el concepte de performance, d'altra banda, va posar l'èmfasi en el funcionament de l'edifici. Això comportava considerar l'edifici com un producte tecnològic o un artefacte amb uns objectius a complir, més que com un objecte artístic amb significat. Per integrar l'DBP en el projecte arquitectònic, van començar a plantejar-se mètodes de disseny que facilitessin la recerca d'una forma adequada a un programa de necessitats, emprant per a això les tècniques i eines utilitzades en la creació de productes tecnològics. Tot i que aquests mètodes de disseny es van postular com una solució a problemes cada vegada més complexos, no van tenir l'efecte esperat. Es va posar de manifest la impossibilitat de prescindir del valor estètic i simbòlic de la arquitectura que el DBP, tal com s'emprava en l'enginyeria de sistemes, obviava. L'arquitectura postmoderna va entendre que una de les funcions de l'arquitectura era comunicar i, per això, va recórrer a teories lingüístiques per explicar els mecanismes pels quals les formes arquitectòniques adquireixen significat. A la fi del segle XX, els avanços en les eines de simulació van permetre replantejar la necessitat del DBP en l'arquitectura: no es considerava ja com un mètode per crear edificis capaços de complir amb uns requisits predeterminats, sinó més aviat per explorar possibilitats formals utilitzant els valors de les prestacions com a inputs en el procés de disseny. Aquest procés de generació de la forma a partir d'unes prestacions es va materialitzar en edificis com el City Hall London (2002) i el Swiss Re Building (2004) de Norman Foster, i el Bird 's Nest (2008) i Beijing National Stadium (2009) d'Herzog & de Meuron; edificis que són significatius social, cultural i econòmicament, i que al mateix temps aspiren a ser eficients des del punt de vista constructiu i energètic. Aquestes obres exemplifiquen l'anomenada “arquitectura performativa” (performative architecture), que és el resultat d'un “disseny performatiu” (perfomative design), és a dir, de retroalimentar la generació de la forma amb la informació sobre les prestacions de l'edifici. El propòsit d'aquesta tesi és comprendre i valorar el potencial que ofereix la metodologia del disseny basat en prestacions per projectar i construir edificis energèticament eficients. Això comporta, en primer lloc, afrontar una sèrie de qüestions fonamentals, com són la naturalesa artística i científica de la arquitectura, la sistematització del procés de disseny i el paper de l'ordinador en aquest procés, i, finalment, el caràcter d’objecte artístic i de producte tecnològic que tenen els edificis. Es tracta així mateix d'identificar els problemes que cal superar perquè el DBP pugui arribar a consolidar-se al projecte d'arquitectura, així com de suggerir solucions als mateixos. En l'actualitat, l'aplicació del DBP en l'àmbit del projecte d'edificis energèticament eficients és encara limitada, com ho demostra el fet que en la pràctica professional se segueixin emprant eines de simulació principalment en les etapes finals del projecte, per tal de verificar el compliment amb la normativa o per aconseguir la certificació energètica, en lloc d'emprar-se per donar suport a la presa de decisions al llarg de tot el procés de disseny d’un edifici, des de les seves fases inicials fins a la seva construcció i ulterior ús. Així, davant la falta de mètodes i eines que facilitin la presa de decisions a partir d'informació avalada i contrastada empíricament, les decisions crucials que determinen l'eficiència energètica d'un edifici es prenen de manera intuïtiva, basant-se en l'experiència i el coneixement dels projectistes. Són necessàries, per tant, estratègies projectuals que permetin integrar la metodologia basada en el DBP en el procés de projecte. Amb aquesta finalitat, s'ha analitzat el procés de projecte que va precedir a la construcció d'un edifici d'habitatges projectat per complir amb la normativa d'eficiència energètica vigent, per tal de proposar un procés de projecte alternatiu basat en l'aplicació del DBP. La comparació d'ambdós processos projectuals, el que es va aplicar a la construcció de l'edifici i el procés alternatiu basat en el DBP, ha permès constatar l'eficàcia de les estratègies projectuals proposades per crear edificis energèticament eficients.En el contexto actual, en el que el ahorro en el consumo de energía se ha convertido en un objetivo prioritario para la arquitectura, son necesarios métodos y herramientas que permitan proyectar con eficacia edificios energéticamente eficientes. El diseño basado en prestaciones (performance-based design o PBD) es un método de diseño que aspira a mejorar la toma de decisiones durante el proyecto con el fin de garantizar que una vez construido el edificio cumplirá con los requisitos prestablecidos. El diseño basado en prestaciones (DBP) surgió a partir de la Investigación Operativa (IO) y el Análisis de Sistemas (AS), disciplinas que se desarrollaron durante la Segunda Guerra Mundial con el fin de mejorar la toma de decisiones en el ámbito militar. Mediante el DBP se “simulaban”, empleando modelos matemáticos y con el apoyo de la tecnología informática, los efectos de soluciones alternativas para elegir aquella que mejor cumplía unos objetivos determinados. La reducción de errores en la toma de decisiones fue considerada una de sus ventajas principales, y artefactos tecnológicos como misiles y cohetes, y también el ordenador, fueron sus productos más destacados. Durante la segunda mitad del siglo XX, el DBP comenzó a introducirse en el ámbito de la arquitectura. El concepto de performance se contrapuso a la noción de función que había prevalecido en el discurso arquitectónico desde el siglo XIX, y que constituyó uno de los dogmas del movimiento moderno. Mientras que el debate sobre la función en la arquitectura se había centrado hasta entonces en el carácter representativo del edificio, es decir, en la capacidad de la forma para expresar la función en términos estéticos, el concepto de performance, por otra parte, puso el énfasis en el funcionamiento del edificio. Esto conllevaba considerar el edificio como un producto tecnológico o un artefacto con unos objetivos a cumplir, más que como un objeto artístico con significado. Para integrar el DBP en el proyecto arquitectónico, comenzaron a plantearse métodos de diseño que facilitasen la búsqueda de una forma adecuada a un programa de necesidades, empleando para ello las técnicas y herramientas utilizadas en la creación de productos tecnológicos. A pesar de que estos métodos de diseño se postularon como una solución a problemas cada vez más complejos, no tuvieron el efecto esperado. Se puso de manifiesto la imposibilidad de prescindir del valor estético y simbólico de la arquitectura que el DBP, tal como se empleaba en la ingeniería de sistemas, obviaba. La arquitectura postmoderna entendió que una de las funciones de la arquitectura era comunicar y, por ello, recurrió a teorías lingüísticas para explicar los mecanismos por los que las formas arquitectónicas adquieren significado. A finales del siglo XX, los avances en las herramientas de simulación permitieron replantear la necesidad del DBP en la arquitectura: no se consideraba ya como un método para crear edificios capaces de cumplir con unos requisitos predefinidos, sino más bien para explorar posibilidades formales utilizando los valores de las prestaciones como inputs en el proceso de diseño. Este proceso de generación de la forma a partir de unas prestaciones se materializó en edificios como el City Hall London (2002) y el Swiss Re Building (2004) de Norman Foster, y el Bird’s Nest (2008) y Beijing National Stadium (2009) de Herzog & De Meuron; edificios que son significativos social, cultural y económicamente, y que al mismo tiempo aspiran a ser eficientes desde el punto de vista constructivo y energético. Estas obras ejemplifican la denominada “arquitectura performativa” (performative architecture), que es el resultado de un “diseño performativo” (perfomative design), es decir, de retroalimentar la generación de la forma con la información acerca de las prestaciones del edificio. El propósito de esta tesis es comprender y valorar el potencial que ofrece la metodología del diseño basado en prestaciones para proyectar y construir edificios energéticamente eficientes. Esto conlleva, en primer lugar, afrontar una serie de cuestiones fundamentales, como son la naturaleza artística y científica de la arquitectura, la sistematización del proceso de diseño y el papel del ordenador en este proceso, y, finalmente, el carácter de objeto artístico y de producto tecnológico que tienen los edificios. Se trata asimismo de identificar los problemas que hay que superar para que el DBP pueda llegar a consolidarse en el proyecto de arquitectura, así como de sugerir soluciones a los mismos. En la actualidad, la aplicación del DBP en el ámbito del proyecto de edificios energéticamente eficientes es aún limitada, como lo demuestra el hecho de que en la práctica profesional se sigan empleando herramientas de simulación principalmente en las etapas finales del proyecto, con el fin de verificar el cumplimiento con la normativa o para conseguir la certificación energética, en lugar de emplearse para apoyar la toma de decisiones a lo largo de todo el proceso de diseño de un edificio, desde sus fases iniciales hasta su construcción y ulterior uso. Así, ante la falta de métodos y herramientas que faciliten la toma de decisiones a partir de información avalada y contrastada empíricamente, las decisiones cruciales que determinan la eficiencia energética de un edificio se toman de manera intuitiva, basándose en la experiencia y el conocimiento de los proyectistas. Son necesarias, por tanto, estrategias proyectuales que permitan integrar la metodología basada en el DBP en el proceso de proyecto. Con este fin, se ha analizado el proceso de proyecto que precedió a la construcción de un edificio de viviendas proyectado para cumplir con la normativa de eficiencia energética vigente, con el fin de proponer un proceso de proyecto alternativo basado en la aplicación del DBP. La comparación de ambos procesos proyectuales, el que se aplicó en la construcción del edificio y el proceso alternativo basado en el DBP, ha permitido constatar la eficacia de las estrategias proyectuales propuestas para crear edificios energéticamente eficientes.Reducing energy consumption has become a priority for contemporary architecture. Consequently, methods and tools to effectively design energy-efficient buildings are needed. Performance-based design (PBD) is a design method that aims to improve decision making during the design process in order to ensure that, once built, a building will meet the predefined requirements. PBD emerged from Operational Research (OR) and Systems Analysis (SA), two disciplines developed during the Second World War to improve military decision-making. PBD was used to “simulate” alternative solutions using mathematical models and computer technology, in order to choose the one that best met some previously determined objectives. One of its main advantages was the reduction of errors in decision making, while its most outstanding products were technological devices such as missiles and rockets, and also the computer. During the second half of the 20th century, PBD began to be introduced in the field of architecture. The concept of performance was played against the notion of function, which prevailed in the architectural discourse since the 19th century and was a dogmatic idea of the modern movement. While the notion of function in architecture focused on the representative character of the building, that is, the capacity of the form to express the function in aesthetic terms, on the other hand, the concept of performance emphasized on the operability of the building. This entailed considering the building as a technological product, or an artefact with some objectives to fulfil, instead of an artistic and meaningful object. Design methods were developed in order to integrate PBD in architectural design, with the objective of easing the search of a form suitable to program needs, by applying techniques and tools used in the creation of technological products. Although these design methods were postulated as a solution to increasingly complex problems, they did not have the expected effect. It became then evident the impossibility to dispense with the aesthetic and symbolic qualities of architecture, which the PBD, as it was being applied in systems engineering, ignored. Postmodern architecture remarked that one of the functions of architecture was to communicate and, therefore, it applied linguistic theories to explain the mechanisms by which architectural forms acquire meaning. The advances in simulation tools at the end of the 20th century led to reconsider the need for PBD in architecture: it was no longer meant to be a method to create buildings capable of fulfilling predefined requirements, but rather to explore formal possibilities using the performance values as inputs to the design process. This process of generating the form considering its performance gave rise to buildings such as the City Hall London (2002) and the Swiss Re Building (2004) by Norman Foster, and the Bird's Nest (2008) and Beijing National Stadium (2009) by Herzog & De Meuron; buildings that are socially, culturally and economically meaningful and at the same time aspire to be efficient from the constructive and energetic perspective. These works exemplify the so-called “performative architecture”, which is the result of a “performative design”; that is, a generative process driven by performance. The purpose of this thesis is to understand and assess the potential of PBD to design and build energy-efficient buildings. This purpose entails, in the first place, facing up fundamental questions such as the artistic and scientific nature of architecture, the systematization of the design process and the role of the computer in this process, and finally, the artistic and technological nature of a building. It also implies identifying the problems that must be overcome in order to strengthen the use of PBD in architectural design, and suggesting solutions to them. Nowadays, the application of PBD in the design of energy-efficient buildings is still limited. This is evidenced by the fact that, in professional practices, simulation tools are mainly used in the final stages of the design in order to check regulations or to obtain an energy certification, instead of being applied to support decision making throughout the entire building design process, from its initial phases to its construction and subsequent use. In the absence of methods and tools that facilitate a decision-making process based on reliable and verifiable information, some crucial decisions that determine the energy efficiency of a building are taken intuitively, on the basis of the experience and knowledge of the designers. Therefore, there is a need of developing strategies to integrate the methodology based on PBD in the design process. For that purpose, the design process of a residential building designed to comply with current energy efficiency regulations has been analysed, in order to propose an alternative design process based on PBD. The comparison of both processes, the one that was applied in the construction of the building and the alternative process based on PBD, made it possible to verify the effectiveness of the proposed design strategies to create energy-efficient buildings