Thomas WortmannUniversität Stuttgart · Institute for Computational Design and Construction
Thomas Wortmann
PhD (Architecture and Sustainable Design) MSc (Design and Computation) MArch
About
54
Publications
96,139
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710
Citations
Citations since 2017
Introduction
I am an architect with extensive experience in computational design, performance simulation and optimization. I have developed Opossum, a machine-learning-based optimization tool for Grasshopper, a parametric modelling platform. I recently completed my PhD. My thesis tests the performance of different optimization methods on problems from structure, energy and daylighting and aims to better integrate optimization into design processes via a novel, interactive visualization method.
Additional affiliations
September 2018 - August 2020
January 2014 - August 2018
Publications
Publications (54)
Sustainable design requires holistic decision making already in the feasibility stage. One critical aspect of a buildingś sustainability is its operational energy consumption, but energy simulations typically are too time‐consuming for early, fast‐paced design phases. Data‐based, Machine Learning models – so called surrogates – can replace time‐con...
This research proposes a design to fabrication data framework for multi-actor fabrication environments with robotic and human actors. The framework generates and exchanges fabrication data between the design elements and the fabrication environment. It features a uniform task data model to represent all processes in the fabrication procedure and li...
Design or construction constraints are often considered only in later phases of a linear design process, which leads to costly revisions during construction. Knowledge bases can include logic rules to check constraints and are a powerful tool for representing knowledge on the Semantic Web. Knowledge bases contain facts and rules. The Buildings and...
AI planning aims to automate the reasoning process that underlies the plan formulation
to achieve a particular goal for a particular problem. Research in this field has focused on symbolic methods -which represent knowledge with human readable symbols- to efficiently and systematically produce plans, i.e., sequences of actions to be performed, from...
Der Aufsatz bietet eine Übersicht über aktuelle Methoden der Datenintegration, künstlichen Intelligenz (KI), Optimierung und Regelungstechnik und ihre (potenziellen) Anwendungen in Gebäudeplanung und Bau. Die Übersicht behandelt sowohl symbolische KI‐Methoden als auch subsymbolische KI‐Methoden bzw. maschinelles Lernen. Der Aufsatz stellt diese Met...
In the building industry, disciplines have specific requirements for capturing, storing and representing information. As a result, one physical object yields several disciplinary representations, allowing designers to describe design options discipline-specifically and thus explore design differently. In a co-design approach, data from disciplines...
Architecture, engineering, and construction (AEC) projects require multidisciplinary solutions; therefore, one physical asset results in several disciplinary representations. Interoperability problems between different software often hinder disciplinary data integration, which prevents the recognition of violated design constraints until it is too...
At the Institute for Computational Design and Construction (ICD) at the University of Stuttgart, its founding director Achim Menges, who also directs the Cluster for Excellence for Integrative Computational Design and Construction for Architecture (IntCDC), and tenure‐track professor Thomas Wortmann illustrate some of their group's research into th...
This study proposes and tests methods for computational multi-objective optimization (MOO) for circular economy (CE) product design. Current CE design frameworks and assessments fail to address two key areas in which computational optimization can add value: identifying the best-performing solutions among many options and managing multiple potentia...
This paper develops a workflow to train machine learning (ML) models with a small dataset from physical samples to predict the curvatures of self-shaping wood bilayers based on local variations in the grain. In contrast to state-of-the-art predictive models, specifically 1.) a 2D Timoshenko model and 2.) a 3D numerical model with a rheological mode...
In this article, we present a procedure to derive algebraic descriptions from geometric descriptions of trimmed hyperbolic paraboloid (or ‘hypar’) surfaces. We contextualise this procedure historically, and we illustrate its application using the 1958 Philips Pavilion by Le Corbusier and Iannis Xenakis as a case study. The procedure uses parametric...
Bending Blossom provides visitors with the feeling of being in a bamboo forest. The structure takes advantage of bamboo’s elasticity. Bent bamboo poles of the structure transfer horizontal loads and reduce the risk of buckling under vertical loads. A green roof serves as a thermal buffer that provides a comfortable micro-climate with natural ventil...
Although there is a substantial body of academic literature on Architectural Design Optimization (ADO), not much is known about actual ADO practices and user experiences. This paper presents results from an international user study of ADO with 186 respondents from various disciplines in architecture and building engineering. Compared to earlier use...
This paper describes a method to understand and digitally reconstruct two sculptures by Gertrud Goldschmidt, a German-born, Venezuelan artist also called Gego. Gego is best known for her series of works called “Reticuláres”. These three-dimensional and open installations, mostly hanging freely in space, are playing with the concept and perception o...
This paper addresses the limitations of existing Solar Envelope (SE) methods to explore the trade-offs of solar radiation and urban shading, and to simultaneously account for several different Key Performance Indicators (KPIs). It offers an alternative parametric workflow-the Solar Block Generator (SBG)-which is based on an additive voxelization me...
This paper explores the trade-off between redeveloping an urban site with higher density and maintaining solar access for the surrounding context in the hot and dry climate of Tel Aviv. Such trade-offs are important for future urban development in the Middle East, where densification is a demographic and environmental need. We explore this trade-of...
This paper explores the use of autoencoders and function approximation to explore design spaces and fitness landscapes resulting from optimization, i.e., post-optimization results. The paper proposes a methodology exploring high-dimensional design space and how it relates to performance. We use dimensionality reduction to reduce complexity and to c...
Computational Fluid Dynamics (CFD) simulation is an important tool in the built environment to analyse wind flow. However, long simulation times limit their utility in fast-paced design processes, especially in larger (urban) scales and in design exploration methods. Two possible approaches to reduce computational cost are: (1) Simplified models su...
For almost two decades, the Zero Energy Buildings (ZEB) standard has epitomized a commitment to the high energy performance of buildings. Nevertheless, the applicability of ZEB in hot climates is currently limited and furthermore, in light of the current limitations of traditional building energy modeling methods, new methods are necessary to effec...
Using an integrated workflow with parametric design, Computational Fluid Dynamic (CFD) and Fast Fluid Dynamic (FFD) simulations, structural analysis and optimization, this paper evaluates the relative suitability of CFD and FFD simulations for Aerodynamic Shape Optimization (ASO). Specifically, it applies RBFOpt, a model-based optimization algorith...
This paper analyzes eight assumptions that underlie the general consensus in the computer-aided architectural design community that multi-objective optimization is more appropriate for and more analogous to architectural design processes than single-objective optimization. The paper discusses whether (a) architectural problems are best formulated a...
The interest to find cost-optimal zero-energy solutions for building, using multi-objective optimization, has risen dramatically over the last decade. Accordingly, several studies have been carried out, proposing new methods and tools. None, however, has introduced a simplified approach that is viable by a broader range of users. This study address...
Environmental simulation supports the design of more sustainable, zero-energy neighborhoods, especially when leveraged with multi-objective optimization. This study explores the tradeoff between urban density and energy balance-specifically, monthly load match between energy usage and generation-in terms of courtyard, slab, and tower typologies for...
In this paper, we present a procedure to derive algebraic parameters from geometrically described truncated hyperbolic paraboloid surfaces. The procedure uses parametric modelling and optimisation to converge on close algebraic approximations of hyperbolic paraboloid geometry through a successive breakdown of vast search spaces. We illustrate this...
In sustainable building design, daylight improves occupants' wellbeing and reduces electric lighting use, but glazed areas can increase energy consumption for heating and cooling. Conflicting objectives such as daylight and energy consumption are the primary motivation behind multi-objective optimization. This paper presents the multi-objective opt...
Although there is a substantial body of academic literature on Architectural Design Optimization (ADO), not much is known about actual ADO practices. This paper presents results from a user study of ADO in Grasshopper and compares them with previous studies. Compared to these studies, this anonymous, web-based survey employed a more relevant sample...
Structural membranes exhibit advantages over slab and frame structures, accommodating large deformations while still elegantly combining spatial enclosure with material efficiency. One of the most promising types of membrane structures are membrane tensegrity structures, which are composed of discontinuous struts embedded in a tensile membrane. To...
When applying black-box optimization (BBO) algorithms there seems to be a lack of guidelines on which algorithm to select and how to properly tune their algorithmic parameters. Many benchmarks are conducted either on large sets of mathematical test functions or on few building simulation problems. This inhibits us from drawing generalizable conclus...
This paper introduces performance-informed design space exploration (DSE) to question the relationship between explicit, quantitative optimization problems and "wicked", co-evolving architectural design problems and to support the reframing of architectural design optimization as a medium for reflection. The paper proposes selection, refinement, an...
This study investigates the performance of a wide selection of single objective black-box optimization algorithms (optimizers) when applied to a large set of building energy simulation problems from the literature. Optimizers include randomized, deterministic and model-based algorithms. We also study the impact of tunable hyper-parameters on perfor...
This study investigates the performance of a wide selection of single objective black-box optimization algorithms (optimizers) when applied to a large set of building energy simulation problems from the literature. Optimizers include randomized, deterministic and model-based algorithms. We also study the impact of tunable hyper-parameters on perfor...
Increasing applications of parametric design and performance simulations by architectural designers present opportunities to design more resource and energy efficient buildings via optimization. But Architectural Design Optimization (ADO) is less widespread that one might expect, due to, among other challenges, the problematic integration of optimi...
This article presents benchmark results from seven simulation-based problems from structural, building energy, and daylight optimization. Growing applications of parametric design and performance simulations in architecture, engineering, and construction allow the harnessing of simulation-based, or black-box, optimization in the search for less res...
Increasing applications of parametric design and performance simulations by architectural designers present opportunities to design more resource and energy efficient buildings via optimization. But Architectural Design Optimization (ADO) is less widespread than one might expect, due to, among other challenges, (1) lacking knowledge on simulation-b...
Computer-based shape grammar implementations aim to support creative design exploration by automating rule-application. This paper reviews existing shape grammar implementations in terms of their algorithmic complexity, extends the definition of shape grammars with sets of transformations for rule application, categorizes (parametric and non-parame...
This chapter presents black-box (or derivative-free) optimization from the perspective of architectural design optimization. We introduce and compare single- and multi-objective optimization, discuss applications from architectural design and related fields, and survey the three main classes of black-box optimization algorithms: metaheuristics, dir...
Model-based optimization is an innovative optimization strategy and particularly appropriate for time-intensive performance simulations. To demonstrate this appropriateness, the paper reviews simulation-based optimization algorithms and benchmarks several (single- and multi-objective) optimization tools on two problems involving annual daylight and...
This paper examines Parametric Design (PD) in contemporary architectural practice. It considers three case studies: The Future of Us pavilion, the Louvre Abu Dhabi and the Morpheus Hotel. The case studies illustrate how, compared to non-parametrically and older parametrically designed projects, PD is employed to generate, document and fabricate des...
This paper considers which black-box optimization methods are most appropriate for building energy optimization by revisiting a seminal work concerned with this question. We benchmark three categories of black-box optimization methods—(1) direct search, (2) metaheuristics and (3) model-based methods—on three building energy optimization problems. C...
This paper presents Opossum, a new optimization plug-in for Grasshopper, a visual data-flow modelling software popular among architects. Opossum is the first publicly available, model-based optimization tool aimed at architectural design optimization and especially applicable to problems that involve time-intensive simulations of for example day-li...
This article presents a method to visualize high-dimensional parametric design spaces with applications in computational design processes and interactive optimization. The method extends Star Coordinates using a triangulation-based interpolation with Barycentric Coordinates. It supports the understanding of design problems in architectural design o...
![Figure 3: Preliminary structural system concepts [Passage Projects]](profile/Thomas-Wortmann/publication/309134544/figure/fig1/AS:614329493766146@1523478973571/Preliminary-structural-system-concepts-Passage-Projects_Q320.jpg)
![Figure 4: Exploded view [Passage Projects]](profile/Thomas-Wortmann/publication/309134544/figure/fig2/AS:614329493757966@1523478973612/Exploded-view-Passage-Projects_Q320.jpg)
![Figure 5: Orientation of the central shell arches [Passage Projects]](profile/Thomas-Wortmann/publication/309134544/figure/fig4/AS:668790161412099@1536463408077/Orientation-of-the-central-shell-arches-Passage-Projects_Q320.jpg)
![Figure 12: Arch Fabrication Drawing [Passage Projects]](profile/Thomas-Wortmann/publication/309134544/figure/fig3/AS:614329497972736@1523478974065/Arch-Fabrication-Drawing-Passage-Projects_Q320.jpg)
The " future of us " exhibition celebrated Singapore's Golden Jubilee. The visitors of the exhibition experienced a stunning play of light and shade cast by a metal lattice, composed of a main steel structure that supports 11000 perforated aluminium panels, spanning approx. 50m and rising to 16m. From start of design to completion of installation w...
This paper presents a novel method to visualize high dimensional parametric design spaces with applications in computational design space exploration. Specifically, the visualization method presented here supports the understanding of design problems in architectural design optimization by allowing designers to move between a high dimensional desig...
Black-box optimization methods play an important role in automated design space exploration, but to-date have not been systematically compared on problems from architectural design optimization. This paper presents a quantitative comparison of the three major types of black-box optimization: metaheuristics, direct search, and model-based methods. W...
Climate change, resource depletion, and worldwide urbanization feed the demand for more energy and resource-efficient buildings. Increasingly, architectural designers and consultants analyze building designs with easy-to-use simulation tools. To identify design alternatives with good performance, designers often turn to optimization methods. Random...
Gentrification is a dynamic, globalized urban process whose complex definition varies with stakeholder perspectives. This complexity makes it challenging for researchers to study the impact of gentrification, and difficult for planners to anticipate the effects of gentrification with planning policy. This paper proposes to model gentrification as a...
We have developed a modular approach to the parametric design of a patterned façade for tropical climates, using a "lighter" data set and model that integrates a number of performance considerations. This modular approach separates the façade's design into form, façade pattern, façade density requirements, and façade components, and reintegrates th...
This paper deals with an application of optimization in architectural design. Formally, we consider the problem of optimizing a function that can only be evaluated through an expensive oracle. We assume that the analytical expression of the function is unknown and first-order information is not available. This situation frequently occurs when each...
Computational design tools in architecture currently fall into two broad categories: Tools for representation and tools for generative design, including scripting. However, both categories address only relatively methodical aspects of designing, and do little to support the design freedom and serendipitous creativity that, for example, is afforded...
Is Structuralism a dead branch on the tree of architectural history, or can some of its ideas be revived in a contemporary context? In trying to answer this question, two theoretical design projects demonstrate how structuralist thinking can be transformed and serve as an inspiration for the use of contemporary digital design techniques like parame...
Questions
Question (1)
I have a question regarding the Hypervolume indicator in multi-objective optimization:
As far as I know, the Hypervolume is the volume of the trade-off space covered by the Pareto-front. I.e., finding the best possible front implies maximizing the Hypervolume.
Does this definition imply that we want to minimize our multiple objectives? What happens to the sign of the Hypervolume when we are maximizing one or more of the objectives? In other words, are we always trying to maximize the Hypervolume, or are there cases where we want to minimize?
Projects
Projects (7)
Performance Explorer is an interactive and intuitive visual tool for performance-informed design space exploration. Performance Explorer uses machine learning and data visualization to visualize a single-objective optimization problem's fitness landscape with real-time performance feedback through surrogate models. Performance Explorer interacts with Grasshopper to allow designers to explore the corresponding designs. We hope that Performance Explorer will assist designers in interpreting architectural design optimization results and foster their understanding of the correlation between design decisions and performance criteria - for the design of a better tomorrow!
Download the Performance Explorer from: https://www.food4rhino.com/en/app/opossum-optimization-solver-surrogate-models
Bench-marking of the exisitng optimization algorithms for design applications, development of new tools and methods, and popularization of ADO methods in practice.
