Cette thèse porte sur la création interactive intuitive de formes 3D, justifié pour les artistes par un besoin d'efficacité et d'expressivité et pour le grand public par la démocratisation d'usages de la modélisation numérique pour les jeux vidéo ou pour les imprimantes 3D. Dans ce cadre, pour trouver des nouvelles formes d'interactions, nous avons développé des modeleurs et des techniques de modélisation : un modeleur de formes libres 3D par métaphore de peinture, un modeleur vectoriel temps réel de paysages ainsi qu'un modeleur de paysages par croquis vu de la première personne. Les contributions scientifiques vont d'un opérateur de mélange implicite qui garanti la localité du mélange, à l'utilisation qu'une formulation bi-harmonique pour la modélisation de terrains permettant une modélisation fine, intuitive et temps réel de terrains; en passant par la modélisation de paysages à partir de croquis composé de silhouettes vus de la première personne. / This thesis focuses on the interactive intuitive creation of 3D Models. Improvment of modeling tools for artists is still an active research mater especialy concerning efficiency and expressiveness. Moreother video games or 3D printers are make the use of modeling tools more common by the general public. In this context, to find new forms of interaction, we have developed modelers and modeling techniques: a 3D free-form modeler which uses a painting metaphor for creation, a vector-based real-time landscapes modeler as well as a sketch-based landscapes modeler that uses first person drawnings. Scientific contributions range from a blending operator for implicit modeling that guarantees the locality of the blend. The use for a bi-harmonic formulation for landscape modeling that allow fine, intuitive and real-time terrain modeling. Finally through landscape modelisation using sketches composed of silhouettes seen from the first person point of view.

L'animation expressive permet des styles de mouvements exagerés et artistiques comme l'étirement de parties du corps ou encore l'animation de créatures imaginaires comme un dragon. Créer ce genre d'animation nécessite des outils assez flexible afin de déformer les personnages en des poses quelconques, ainsi que de pouvoir contrôler l'animation à tout moment dans le temps. L'approche acutelle pour l'animation expressive est le keyframing: une approche manuelle avec laquelle les animateurs déforment leur personnage un moment spécifique dans le temps en cliquand et glissant la souris sur une partis spécifique du corps---un à la fois. Malgré le fait que cette approche soit flexible, il est difficile de créer des animations de qualité qui suivent les principes artistiques, puisque le keyframing permet seulement qu'un contrôle local spatiallement et temporellement. Lorsqu'ils dessinent des poses ou des mouvements, les artistes s'appuient sur différentes abstractions sous forme de croquis qui facillitent la réalisation de certain principes artistiques. Par example, certains animateurs dessinent des lignes d'action afin de créer une pose plus lisible et expressive. Afin de coordonner un mouvement, les animateurs vont souvent dessiner des abstractions de mouvement comme des demi-cercles pour des sauts, ou des boucles pour des pirouettes---leur permettant de pratiquer la coordination du mouvement. Malheureusement, ces outils artistiques ne font pas partis de l'ensemble d'outils de keyframing actuelle. Le fait que l'on ne puisse pas employer les même outils artistiques pour animater des personnages 3D a une forte conséquence: les outils d'animation 3D ne sont pas employés dans le processus créatif. Aujourd'hui, les animateurs créent sur du papier et utilisent le keyframing seulement à la fin pour réaliser leur animation. La raison pour laquelle nous n'avons pas ces outils artistiques (ligne d'action, abstractions de mouvement) en animation 3D, est parce qu'il manque une compréhension formelle de ceux-ci qui nous permettrais d'exprimer la forme du personnage---potentiellement au cours du temps---en fonction de la forme de ces croquis. Ainsi la contribution principale de cette thèse est une compréhension formelle et mathématique des abstractions de forme et de mouvement courrament employées par des artistes, ainsi qu'un ensemble d'algorithme qui permet l'utilisation de ces outils artistiques pour créer des animations expressives. C'est-à-dire que les outils développés dans cette thèse permettent d'étirer des parties du corps ainsi que d'animer des personnages de différentes morphologies. J'introduis aussi plusieurs extentions à ces outils. Par example, j'explore l'idée de sculpter du mouvement en permettant à l'artiste de dessigner plusieurs couches de mouvement une par dessus l'autre, de twister en 3D les croquis, ou encore d'animer un croquis ligne comme un élastique. Les contributions principales de cette thèse, aussi résumé ci-dessous: -La ligne d'action facilitant la création de poses expressives en dessinant directement le flow complet du personnage. -La courbe spatio-temporelle qui permet de spécifier un mouvement coordoné complet avec un seul geste (en dessinant une seule courbe), applicable à n'importe quel personnage 3D. -Un algorithme de matching rapide et robuste qui permet du ``squash and stretch''. -La ligne d'action élastique avec des attachements dynamiques à la ligne permettant d'animer un personnages à plusieurs jambes (bras) avec une seule ligne 2D animée. / Free-form animation allows for exaggerated and artistic styles of motions such as stretching character limbs and animating imaginary creatures such as dragons. Creating these animations requires tools flexible enough to shape characters into arbitrary poses, and control motion at any instant in time. The current approach to free-form animation is keyframing: a manual task in which animators deform characters at individual instants in time by clicking-and-dragging individual body parts one at a time. While this approach is flexible, it is challenging to create quality animations that follow high-level artistic principles---as keyframing tools only provide localized control both spatially and temporally. When drawing poses and motions, artists rely on different sketch-based abstractions that help fulfill high-level aesthetic and artistic principles. For instance, animators will draw textit{lines of action} to create more readable and textit{expressive} poses. To coordinate movements, animators will sketch textit{motion abstractions} such as semi-circles and loops to coordinate a bouncing and rolling motions. Unfortunately, these drawing tools are not part of the free-form animation tool set today. The fact that we cannot use the same artistic tools for drawing when animating 3D characters has an important consequence: 3D animation tools are not involved in the creative process. Instead, animators create by first drawing on paper, and only later are 3D animation tools used to fulfill the pose or animation. The reason we do not have these artistic tools (the line of action, and motion abstractions) in the current animation tool set is because we lack a formal understanding relating the character's shape---possible over time---to the drawn abstraction's shape. Hence the main contribution of this thesis is a formal understanding of pose and motion abstractions (line of action and motion abstractions) together with a set of algorithms that allow using these tools in a free-form setting. As a result, the techniques described in this thesis allow exaggerated poses and movements that may include squash and stretch, and can be used with various character morphologies. These pose and animation drafting tools can be extended. For instance, an animator can sketch and compose different layers of motion on top of one another, add twist around strokes, or turning the strokes into elastic ribbons. The main contributions of this thesis are summarized as follows: -The line of action facilitating expressive posing by directly sketching the overall flow of the character's pose. -The space-time curve allowing to draft full coordinated movements with a single stroke---applicable to arbitrary characters. -A fast and robust skeletal line matching algorithm that supports squash-and-stretch. -Elastic lines of action with dynamically constrained bones for driving the motion of a multi-legged character with a single moving 2D line.

Due to its economic importance engineering design as a creative design problem solving has been the research subject of psychologists and design engineers for several years. Observations of designer's thinking and action processes show that especially in the early stages of the design process, in which requirements are clarified and ideas are developed, generating solutions is largely associated with the use of simple external representations such as sketches and material (physical) models. In the represented thesis the use and functions of such external aids were investigated at first with a questionnaire study consulting designers (N = 106) of different industries. The results demonstrate the dominance of sketches as well as the increasing use of CAD already in the early stages of product development. In contrast models are applied to a lesser extent. Thereby simple external aids are not only used as memory-relieving external information storages, but do also support solution development and testing, serve as an analysis aid and contribute helpfully to documentation and communication. Further in an experimental study the use and functions of sketching and manual modelling applied by engineering students and designers (N = 61) while working on two design problems of different complexity with free choice of the support form were analysed. The results verify the essential importance of sketching for the design process, since almost all subjects used sketches to deal with the two design problems, while material models were hardly applied. Again the sketches fulfil different functions, so besides documentation they mainly support solution development. These statement based findings that sketches in addition to their function as external storages for memory relief serve also as thinking aids, thus support the generating and further developing of solution concepts, could be confirmed by observation data based on the analysis of the individual design processes. Finally recommendations for the design of new and advanced computer-assisted design aids could be given. / Das Konstruieren als schöpferisch-entwerfendes Problemlösen (design problem solving) ist aufgrund seiner wirtschaftlichen Bedeutung seit längerem Gegenstand der Forschung von Psychologen und Konstruktionswissenschaftlern. Beobachtungen des Vorgehens des Konstrukteurs zeigen, daß insbesondere in den frühen Phasen des konstruktiven Entwurfsprozesses, in denen Anforderungen geklärt und Ideen generiert werden, die Lösungsentwicklung in hohem Maße durch einfache externe Hilfsmittel, wie Skizzen und gegenständliche Modelle, unterstützt wird. In der dargestellten Dissertation wurde Einsatz und Nutzen dieser Hilfsmittel zunächst anhand einer Befragung von Konstrukteuren (N = 106) verschiedener Branchen untersucht. Die Ergebnisse belegen die Dominanz von Skizzen sowie die Zunahme der Nutzung von CAD bereits in den frühen Phasen der Produktentwicklung. Modelle finden dagegen weniger häufig Verwendung. Einfache externe Hilfsmittel werden dabei nicht nur als gedächtnisentlastende externe Speicher eingesetzt, sondern unterstützen ebenso die Lösungsentwicklung und -überprüfung, dienen als Analysehilfe und tragen hilfreich zur Dokumentation und Kommunikation bei. Weiterhin wurde in einer experimentellen Studie der Einsatz und die Funktionen des Skizzierens und manuellen Modellierens bei der Bearbeitung zweier Konstruktionsprobleme unterschiedlicher Komplexität durch Maschinenbaustudenten und Konstrukteure (N = 61) bei freier Wahl der Unterstützungsform näher untersucht. Die Ergebnisse verifizieren die essentielle Bedeutung des Skizzierens für den konstruktiven Entwurfsprozeß, da nahezu alle Probanden die beiden Konstruktionsprobleme von Anfang an skizzierend bearbeiteten, während einfache Modelle so gut wie gar nicht eingesetzt wurden. Die Skizzen erfüllten wiederum verschiedene Funktionen, neben der Dokumentation wurden sie v.a. zur Lösungsentwicklung verwendet. Dabei konnten diese auf Aussagen beruhenden Erkenntnisse, daß Skizzen neben der Gedächtnisentlastung auch eine Denkhilfe bieten, durch aus der Analyse der Entwurfsprozesse gewonnene Beobachtungsdaten bestätigt werden. Abschließend wurden Gestaltungsempfehlungen für die Neu- und Weiterentwicklung computergestützter Hilfsmittel des konstruktiven Entwurfsprozesses formuliert.

Visualization is an important part of the design process. The sketches that are created during the design process are the visible evidence of the visualization that occurs in the brain. The process of designing involves a conversation that occurs between the student and the sketches created during problem finding and problem solving in the design process. This conversation allows the student to progress through the design process manipulating both the drawn image on paper and the visualization that occurs in their mind until a fitting solution to the problem is found. This study sought a better understanding of this communication style and it's effect on designed final products. Two methods of analysis were utilized in this research. Quantitative analysis was used to measure the correlation between quality of sketching process and the quality of the final designed product. Then multiple case studies were examined to describe in detail the design process styles of three students. First the sketches that were created during the designing of a student project were counted and then evaluated for sketch creativity and sketch efficacy. The final design products were evaluated for project creativeness and project function. Significant positive statistical correlations between the variables were observed. In summary, the quality of sketches and visual thinking during the design process had a measurable positive effect on the final designed solution. / Master of Science

This thesis aims to explore the potential of virtual reality (VR) to promote sustainable behaviours. The literature review draws from various fields that discuss the advantages and limitations of VR in design experiences (Scurati, et al., 2021)and how VR can provide an overview on training and transfer, education, and procedural, cognitive and maintenance training (Psotka, 1995) In virtual reality and education and training paper Joseph Psotka provides a brief overview of existing VR research on. Contributing to this literature in VR and education for designing behaviour change with a sustainability focus, by utilizing VR technology, this research focuses on transforming a carbon calculator into an immersive VR environment with the goal of increasing users’ awareness of carbon emissions. Hence, this research allows individuals with little to no experience to create and be part of immersive experiences that effectively convey information and increase users’ awareness of carbon emissions. Adopting semi-structured interviews and digital material exploration as its research methodology, this study involves participants from different backgrounds and levels of knowledge about carbon emissions aiming to create an immersive experience that could effectively educate and engage users in understanding and addressing sustainability issues. Through the development of a hi-fi prototype, participants who tested the VR experience expressed an increased interest in learning about carbon emissions, indicating the potential of immersive VR in raising awareness and fostering behaviour change. The study was conducted in collaboration with Nordic Waves Group, a Denmark-based organization that focuses on UN’s 17 New World Goals, demonstrates the practical application of the research in a real-world context, aligning with their commitment to the Sustainable Development Goals. The findings of this study emphasize the potential of VR in promoting sustainable behaviours and highlight the importance of incorporating immersive experiences in sustainability education and awareness campaigns. Overall, this research provides insights into the use of VR as a tool for promoting sustainability and offers practical solutions for designing behaviour change interventions with a focus on carbon emissions. / <p>Examensarbetet är utfört vid Institutionen för teknik och naturvetenskap (ITN) vid Tekniska fakulteten, Linköpings universitet</p>

The aim of this thesis is to through a series of co-design explorations develop guidelines for how analogue co-design methods and tools can be digitalized and used for the initial phase of a co-design process in remote settings. To nurture the discussion around how co-design practices can be digitalized several aspects are investigated and focused upon, presenting an overview of relevant factors for future researchers to delve deeper into.  Found challenges revolve around the lack of a shared physical environment, the implementation of physical materials and sketching, and the building of trust and relationships in remote settings.  The final product of this thesis is a set of guidelines that have been established through a series of co-design explorations drawing on perspectives found in both academia and the current industry.

本篇論文建立一個藉由直覺性素描搜尋模型的系統，結合筆觸繪圖搜尋手繪圖與模型。希望可以藉由本系統，提供使用者比起關鍵字或模型搜尋模型，更加方便的模型搜尋工具。系統主要分為建立索引檔、比對特徵向量和使用者介面三個部分。建立索引檔部分要將三維模型處理成資料庫可認知的資料型態，首先將模型旋轉到不同角度並且將之從三維空間描繪成二維模型投影圖，再透過分類演算法把模型投影圖和手繪圖描述為二維特徵向量。比對特徵向量部分需建立手繪圖資料庫和三維模型資料庫的橋梁，藉由計算兩者的特徵向量之間的距離與角度，得到相似度的排序。使用者介面部分提供直覺性使用者繪畫的介面，以不影響使用者創造性的前提下，在使用者繪畫過程中給予最相似於使用者繪畫的手繪圖結果，使用者可以藉由臨摹此結果更貼近所想繪畫的物體，更進一步地取得模型的搜尋結果。最後我們將透過統計方法去驗證系統的有效性。 / We proposed an intuitive model retrieval system with a sketch interface for a database contains sketch drawings and 3D models. Benefit the sketch interface, the proposed system can facilitate the search process better than keyword query or search by 3D model. The system begins with offline indexing preprocess which convert the 3D models into feature vectors. Under best view selection, we render each 3D model into a 2D feature line image. Then classification method will apply the line images and sketching images in model database to build the feature vector. The rank of matching is computed with the angle between the feature vector of input sketch image and feature line images in the database. To extend the usability, we design a sketch interface for searching the best match result during the drawing process. For suggesting the drawing hint, candidate matching results are listed aside to the sketch input screen. We use statistical method to evaluate the feasibility of the proposed system.

Movement-based interactive systems for play came into the spotlight over a decade ago, and were met with enthusiasm by the general public as well as the Human-Computer Interaction research community. Yet a decade of research and practice has not fully addressed the challenge of designing for the moving body and play. This thesis argues that often, the role of the technology to sustain the play activity, and to drive the design process, has been over-emphasized, and has resulted in limited design possibilities. This thesis explores an alternative design approach to address the problem through combining the design of the technology with designing aspects of the social and spatial context where the play activity takes place. The work is grounded in an embodied perspective of experience, action, and design. Methodologically, it belongs to the Research through Design tradition (RtD). A core concept and a characterization of design practices are presented as key contributions. The concept of embodied core mechanics is introduced to frame desirable and repeatable movement-based play actions, paying attention to the way these are supported by design resources including rules, physical and digital artifacts, and the physical and spatial arrangement of players and artifacts. The concept was developed during the two main design cases: the Oriboo case, targeting dance games for children, and the PhySeEar case, targeting rehabilitative therapy for the elderly. It was further substantiated in subsequent external design collaborations. To support the design process, this thesis presents embodied sketching: a set of ideation design practices that leverage the embodied experience and enable designers to scrutinize the desired embodied experience early in the design process. Three forms of embodied sketching are presented: embodied sketching for bodystorming, co-designing with users, and sensitizing designers. Through reframing the design task as one of designing and studying embodied core mechanics, this thesis establishes an alternative approach to design for movement-based play in which significant aspects of the embodied play experience, lead, drive, and shape the design process and the design of the technology.

The task of choosing a preconditioner M to use when solving a linear system Ax=b with iterative methods is often tedious and most methods remain ad-hoc. This thesis presents a randomized algorithm to make this chore less painful through use of randomized algorithms for estimating traces. In particular, we show that the preconditioner stability || I - M-1A ||F, known to forecast preconditioner quality, can be computed in the time it takes to run a constant number of iterations of conjugate gradients through use of sketching methods. This is in spite of folklore which suggests the quantity is impractical to compute, and a proof we give that ensures the quantity could not possibly be approximated in a useful amount of time by a deterministic algorithm. Using our estimator, we provide a method which can provably select a quality preconditioner among n candidates using floating operations commensurate with running about n log(n) steps of the conjugate gradients algorithm. In the absence of such a preconditioner among the candidates, our method can advise the practitioner to use no preconditioner at all. The algorithm is extremely easy to implement and trivially parallelizable, and along the way we provide theoretical improvements to the literature on trace estimation. In empirical experiments, we show the selection method can be quite helpful. For example, it allows us to create to the best of our knowledge the first preconditioning method for kernel regression which never uses more iterations over the non-preconditioned analog in standard settings.

This thesis presents kinematic templates, end-user drawing tools that influence the mouse cursor's movement within specific areas of a digital canvas. Two types of kinematic templates influence the cursor's movement: passive and active templates. Passive templates modify existing movement received from a pointing device to change the cursor's speed or direction of one's stroke. Active templates add movement to the cursor without movement from the pointing device. Since templates are provided as user-specified regions, these regions can be associated with areas of detail and they can be overlapped as a means of function composition. [¶] A kinematic template can be configured to improve upon one's freehand output without producing perfect output. Since templates do not necessarily prescribe geometric output, they constitute a visual composition aid that lies between unaided freehand drawing and drawing aids such as snapping constraints and perfect geometric primitives. [¶] Since kinematic templates can improve upon the consistency of one's strokes, it is beneficial for drawing visual styles such as hatching (an artistic effect that adds depth to a drawing with uniform strokes drawn in close proximity) and repetitive patterns. Since kinematic templates do not prescribe a type of output, one can "fight against" a template's preferred path of movement and discover unexpected, serendipitous outcomes.