SBM05: Sketch Based Interfaces and Modeling 2005

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https://diglib.eg.org/handle/10.2312/421

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3D6B Editor: Projective 3D Sketching with Line-Based Rendering
(The Eurographics Association, 2005) Kallio, Kiia; Joaquim Armando Pires Jorge and Takeo Igarashi
In this work, a system for 3D sketching is presented. Instead of trying to process 3D data as geometric models constructed of surfaces or solids, the data is stored as 3D lines, preserving their form exactly as entered by the user. The 3D input of the system works by projecting 2D input from a single viewpoint to a grid surface that can be manipulated in real time. This enables creation of sketches with complex non-planar 3D strokes while still retaining the essence of pen and paper based sketching.
A Simple-to-Implementation Method for Cutting a Mesh Model by a Hand-Drawn Stroke
(The Eurographics Association, 2005) Mitani, Jun; Joaquim Armando Pires Jorge and Takeo Igarashi
In the field of Computational Geometry, the design of 3D models using hand drawn strokes has been well-studied in recent years as a way to improve user interfaces. When using hand-drawn strokes to design 3D models, an algorithm for cutting a model by a stroke is required. Previous algorithms have concentrated on precision and are expensive to implement. This paper gives priority to simplicity and robustness rather than precision. Firstly, mesh vertices near to the stroke are moved so that they lie on the stroke, to avoid numerical error. Then the stroke is simplified so that it crosses a triangle at most two times. With this approach, the number of patterns of triangle division that a system has to implement is reduced to only three. This reduces the time a developer must take to implement a cut operation for a sketching interface.
Designer s Choice: Constructing a Study to Compare Display Interfaces for Early Design Sketching
(The Eurographics Association, 2005) Hsia, A.; Samoylov, A.; McGovern, A.; Bailey, B.; Joaquim Armando Pires Jorge and Takeo Igarashi
Digital design tools provide several advantages over pen and paper, including a virtually unlimited workspace and easy design storage, transportation, duplication and access. However, the benefits of new tools are limited by the physical interfaces that are used to interact with them. In this paper, we describe and conduct an exploratory study designed to illuminate strengths and weaknesses of three digital sketching interfaces: Separated Overview+Detail (two standard desktop screens), Separated Focus+Context (one standard desktop screen with one large screen), and Single Large-Screen. The experimental tasks focus on the domain of early sketching and prototyping. Users performed one of three tasks on all three displays. Our results suggest that the Focus+Context system elicits higher user satisfaction, and possibly incurs fewer costs on perception resources and performance. Given the exploratory nature of this study, we close with suggestions for further research directions.
Progress in Detection of Axis-Aligned Planes to Aid in Interpreting Line Drawings of Engineering Objects
(The Eurographics Association, 2005) Varley, P. A. C.; Martin, R. R.; Suzuki, H.; Joaquim Armando Pires Jorge and Takeo Igarashi
Freehand sketching is an important part of the conceptual design process, and the increasing number of recent sketching applications shows a developing awareness of this importance. We aim to provide an automated tool to turn engineers freehand sketches into CAD models. This would allow engineers to spend their time more productively and to be more creative. One natural component of such a tool would be a process for identifying axially-aligned planes implied by a natural line drawing. We present an algorithm for identifying such planes. We illustrate its utility by presenting two uses: identifying planes of mirror symmetry in objects and constructing the hidden topology of objects.
Comparing SESAME and Sketching on Paper for Conceptual 3D Design
(The Eurographics Association, 2005) Oh, Ji-Young; Stuerzlinger, Wolfgang; Danahy, John; Joaquim Armando Pires Jorge and Takeo Igarashi
In the early stages of design, several concepts are usually generated to explore the possibilities. This paper investigates how well a computer-based system can support design thinking. SESAME is a novel 3D design system that aims to support creativity during the explorative phase of the design process. We report an evaluation comparing SESAME to paper sketching for early design exploration in an urban design scenario. Through the user evaluation, we illustrate how important it is to support essential properties of traditional sketching, such as rapid creation/ modification, emergent shapes, and tolerance to ambiguity. Additionally, we show that a 3D system can indeed facilitate form exploration at the early stages of design thinking.
ShapeShop: Sketch-Based Solid Modeling with BlobTrees
(The Eurographics Association, 2005) Schmidt, Ryan; Wyvill, B.; Sousa, M. C.; Jorge, J. A.; Joaquim Armando Pires Jorge and Takeo Igarashi
Various systems have explored the idea of inferring 3D models from sketched 2D outlines. In all of these systems the underlying modeling methodology limits the complexity of models that can be created interactively. The ShapeShop sketch-based modeling system utilizes Hierarchical Implicit Volume Models (BlobTrees) as an underlying shape representation. The BlobTree framework supports interactive creation of complex, detailed solid models with arbitrary topology. A new technique is described for inflating 2D contours into rounded three-dimensional implicit volumes. Sketch-based modeling operations are defined that combine these basic shapes using standard blending and CSG operators. Since the underlying volume hierarchy is by definition a construction history, individual sketched components can be non-linearly edited and removed. For example, holes can be interactively dragged through a shape. ShapeShop also provides 2D drawing assistance using a new curve-sketching system based on variational contours. A wide range of models can be sketched with ShapeShop, from cartoon-like characters to detailed mechanical parts. Examples are shown which demonstrate significantly higher model complexity than existing systems.
Sketch-Based Design for Bargello Quilts
(The Eurographics Association, 2005) Coahran, M.; Fiume, E.; Joaquim Armando Pires Jorge and Takeo Igarashi
Quilting is an art form in which amateur craftspeople explore geometry and color to create stunning designs. Bargello is a specific quilt style defined by a clever construction method that imposes constraints on the designs and gives them a characteristic appearance. Currently, Bargello patterns are typically designed manually, in a process that is laborious and time-consuming. We have developed a prototype system in which users can design Bargello quilts quickly and easily by sketching curves with a mouse. As a curve is drawn, the system transforms it into a graceful Bargello curve, composed of corner-connected axis-aligned rectangles, that respects both physical constraints and design constraints intrinsic to the Bargello style. We also provide a design setting that supports design variations typical of Bargello quilts and a set of tools to extend simple designs into complex ones. We conducted an informal evaluation of the system in a series of focus group sessions with potential users from the quilting community. Quilters were enthusiastic about the system and also provided suggestions for improvement.
Sketch-Based Mesh Augmentation
(The Eurographics Association, 2005) Olsen, L.; Samavati, F. F.; Sousa, M. C.; Jorge, J. A.; Joaquim Armando Pires Jorge and Takeo Igarashi
This paper describes a sketch-based method for augmenting geometric meshes with variable-scale sharp features. Such mesh editing operations provide a powerful way to exploit an artist s natural sketching abilities for content creation using existing mesh libraries. We use adaptive subdivision to refine the mesh only in the region of the features and embed the augmentations into the input mesh, maintaining a unified representation. Moreover, we present new templates for adaptive subdivision that minimize the high-valence vertex count while maximizing the number of quadrilaterals in the new mesh, thereby improving its quality.
2D Sketch Based Recognition of 3D freeform Shape by Using the RBF Neural Network
(The Eurographics Association, 2005) Qin, S. F.; Sun, Guangmin; Wright, D. K.; Lim, S.; Khan, U.; Mao, C.; Joaquim Armando Pires Jorge and Takeo Igarashi
This paper presents a novel free-form surface recognition method from 2D freehand sketching. The approach is based on the Radial basis function (RBF), an artificial intelligence technique. A simple three-layered network has been designed and constructed. After training and testing with two types of surfaces (four sided boundary surfaces and four close section surfaces), it has been shown that the method is useful in freeform surface recognition. The testing results are very satisfactory.
SNARF Taxonomies for Sketching Novel and Realistic Functionality
(The Eurographics Association, 2005) Drexelius, Christopher; Talwalkar, Rohit Uday; Cho, Brian; Bailey, Brian P.; Joaquim Armando Pires Jorge and Takeo Igarashi
Paper prototyping is often used during the critical stage of early design. While paper prototyping requires a small time investment, it can fail to accurately convey the application s behavior. Existing computerized tools allow designers to express both appearance and interactions through sketching; designers may even execute their sketches. However, these tools have limitations, such as scalability and an inability to represent some complex behaviors. By asking users to sketch interfaces that are complex and novel, we developed a family of sketching taxonomies. We also created a set of suggested design notations based on the specific behaviors and characteristics users sketched. Furthermore, we developed an iterative user-centric approach that can be used to expand and refine the SNARF taxonomies and suggested notations. Most users, given these suggested notations were able to double their sketched behavior. This result suggests our notations would be a welcome addition to any sketch-based tool. We also identified the potential of color as a linking mechanism.
Sketching Free-form Surfaces Using Network of Curves
(The Eurographics Association, 2005) Das, Koel; Diaz-Gutierrez, Pablo; Gopi, M.; Joaquim Armando Pires Jorge and Takeo Igarashi
This work addresses the issue of generating free-form surfaces using a 2D sketch interface. As the first step in this process, we develop a methodology to sketch 3D space curves from 2D sketches. Since the inverse projection from 2D sketches to 3D curve or surface is a one to many function, there is no unique solution. Hence we propose to interpret the given 2D curve to be the projection of the 3D curve that has minimum curvature among all the candidates in 3D. We present an algorithm to efficiently find a close approximation of this minimum curvature 3D space curve. In the second step, this network of curves along with the boundary information are given to the surface fitting method to generate free-form surfaces.
A Sketch-Based Gesture Interface for Rough 3D Stick Figure Animation
(The Eurographics Association, 2005) Mao, C.; Qin, S. F.; Wright, D. K.; Joaquim Armando Pires Jorge and Takeo Igarashi
This paper introduces a novel gesture interface for sketching out rough 3D stick figure animation. This interface can allow users to draw stick figures with the system automatic assistance in figure proportion control. Given a 2D hand-drawn stick figure under a parallel view, there is a challenge to reconstruct a unique 3D pose from a set of candidates. Our system utilizes figure perspective rendering, and introduces the concept of thickness contrast as a sketch gesture combined with some other constraints/assumptions for pose recovery. The resulting pose can be further corrected, based on physical constraints of human body. Once obtaining a series of 3D stick figure poses, user can easily sketch out motion paths and timing, and add their preferable sound/background. The resulting 3D animation can be automatically synthesized in VRML. This system has been tested on a variety of input devices: electric whiteboard, tablet PC, as well as a standard mouse.
Sketch-based Modeling of Parameterized Objects
(The Eurographics Association, 2005) Yang, Chen; Sharon, Dana; Panne, Michiel van de; Joaquim Armando Pires Jorge and Takeo Igarashi
Sketch-based modeling holds the promise of making 3D modeling accessible to a significantly wider audience than current modeling tools. We present a modeling system that is capable of constructing 3D models of particular object classes from 2D sketches. The core of the system is a sketch recognition algorithm that seeks to match the points and curves of a set of given 2D templates to the sketch. The matching process employs an optimization metric that is based on curve feature vectors, and the search space of possible correspondences is restricted by encoding knowledge about relative part locations into the 2D template. Once a best-fit template is found, a 3D object is constructed using a series of measurements that are extracted from the labelled 2D sketch. We apply our sketch-recognition and modeling algorithms to sketches of cups and mugs, airplanes, and fish. The system allows non-experts to use drawings to quickly create 3D models of specific object classes.
Sketching Cartoons by Example
(The Eurographics Association, 2005) Sykora, D.; Buriánek, J.; Zara, J.; Joaquim Armando Pires Jorge and Takeo Igarashi
We introduce a novel example-based framework for reusing traditional cartoon drawings and animations. In contrast to previous approaches our aim is to design new characters and poses by combining fragments of the original artwork. Using standard image manipulation tool this task is tedious and time consuming. To reduce the amount of manual intervention we combine unsupervised image segmentation, fragment extraction and highquality vectorization. The user can simply select an interesting part in the original image and then adjust it in a new composition using a few control scribbles. Thanks to ease of manipulation proposed sketch-based interface is suitable both for experienced artists and unskilled users (e.g. children) who wish to create new stories in the style of masters. Practical results confirm that using our framework high-quality cartoon drawings can be produced within much shorter time frames as compared with standard approaches.
Retrieving Web Page Layouts using Sketches to Support Example-based Web Design
(The Eurographics Association, 2005) Hashimoto, Yasunari; Igarashi, Takeo; Joaquim Armando Pires Jorge and Takeo Igarashi
It is very difficult for inexperienced users to design good-looking web page layouts. Even with WYSIWYG editors, it is still difficult to obtain desired results because one must combine complicated HTML specific structures. Another reason is that it is inherently difficult for those who have limited artistic talents to design good layout from scratch. We address these problems by providing an environment where one can design web page layouts using existing well-designed web pages on the net as examples. The system basically works as a search system. The user sketches a simple layout as a query and the system returns web pages that have similar appearance. By referring to the example pages, the user can learn the basic principles of HTML design, obtain inspiration for better design, and also can directly use the professionally designed layouts by replacing the contents. This paper describes the user interface and the implementation of the system in detail. It also reports the result of an empirical user study. The users found the system very useful and the layouts designed using the system was scored highly by evaluators.
An Interactive Sketch-based Modeling System using a Topology Library and Subdivision Methods
(The Eurographics Association, 2005) Liu, Weizhong; Kondo, Kunio; Mitani, Jun; Joaquim Armando Pires Jorge and Takeo Igarashi
We present a sketch-based modeling system for interactive modeling of a variety of 3D objects. The idea is to con-struct and modify 3D objects, step by step, using a 2D template topology library. The library, called T-LIB, consists of 2D Edge Graphs and the corresponding algorithms to construct and modify 3D objects. The local part of 3D ob-ject around the sketch lines is analyzed as a 2D Edge Graph. Once the Edge Graph can be matched to a template of T-LIB, the 3D object can be generated in a basic shape reconstruction procedure, or modified in a 3D shape modi-fication procedure. After obtaining the solid model, we use a fillet operation and a subdivision method to generate smooth surface objects.
Sketch-based Segmentation of Scanned Outdoor Environment Models
(The Eurographics Association, 2005) Yuan, Xiaoru; Xu, Hui; Nguyen, Minh; Shesh, Amit; Chen, Baoquan; Joaquim Armando Pires Jorge and Takeo Igarashi
When modeling with scanned outdoor models, being able to select a subset of the points efficiently that collectively represent an object is an important and fundamental operation. Such segmentation problems have been extensively studied, and simple and efficient solutions exist in two dimensions. However, 3D segmentation, especially that of sparse point models obtained by scanning, remains a challenge because of inherent incompleteness and noise. We present a sketched-based interface that allows segmentation of general 3D point-based models. The user marks object and background regions by placing strokes using a stylus, and the tool segments out the marked object(s). To refine the results, the user simply moves the camera to a different location and repeats the process. Our method is based on graph cuts, a popular and well-tested paradigm for segmentation problems. We employ a two-pass process: we use the strokes to perform 2D image segmentation in the projection plane of the camera and use its results for the 3D scanned data segmentation. The advantages of our method are ease of use, speed and robustness. Our method works for general 3D point models and not just range images. Important applications include selection of objects when dealing with large, unorganized point models for refinement, remodeling, meshing, etc.
A Sketching Interface for Modeling and Editing Hairstyles
(The Eurographics Association, 2005) Malik, Shahzad; Joaquim Armando Pires Jorge and Takeo Igarashi
This paper presents interaction techniques and algorithms for modeling and editing virtual 3D hairstyles with a user-friendly sketching interface. Using a pressure-sensitive tablet, a user makes freeform strokes to mimic a number of real-world hairstyling operations such as cutting, combing, curling, frizzing, and twisting. Additionally, the user can perform other localized operations such as implanting new hair strands onto a 3D surface (usually the scalp), lengthening the strands, and adjusting hair density. Virtual hairpins can also be placed onto strands to temporarily fix the position of hair which allows for the creation of more advanced styles such as ponytails. The system runs at interactive rates, thereby providing instant visual feedback to users as they work. Unlike existing hair modeling systems that require hours of complicated control point manipulations and parameter tweaking, our interface allows for creating expressive hairstyles quickly and easily, even for first-time users.
Object Snapping Method using Multi-Resolution Fuzzy Grid Snapping Technique
(The Eurographics Association, 2005) Dematapitiya, Sumudu; Kawazoe, Masatoshi; Khand, Qamar Uddin; Saga, Sato; Joaquim Armando Pires Jorge and Takeo Igarashi
We propose the automatic snapping of objects using the Multi-resolution Fuzzy Grid Snapping (MFGS) for a sketch based CAD system. The sketch based CAD system, which has already been realized, identifies sketch drawings as primitive geometric curve objects, based on the user's drawing manner. While drawing objects of varying fineness, misalignments arise due to unappropriate grid snapping resolution settings. Meanwhile, MFGS is an automatic grid snapping resolution switching mechanism, which snaps a cursor on a multiple grid system, based on the snapping intentions of the user. In this paper, we propose to solve the problem of misalignments of sketched objects of various fineness by applying MFGS to object snapping. To show the effectiveness of this method, we give experiments containing drawings of linear and circular objects of various sizes, drawn with different snapping intentions. By comparing these results with the results of the traditional snapping method, we can see that because of this newly proposed object snapping method, it has become possible to dispense with the manual switching of grid snapping resolutions. Therefore we can say that our snapping method enables the user to draw curves of different fineness, seamlessly and efficiently
A Sketch-Based Interface for Iterative Design and Analysis of 3D Objects
(The Eurographics Association, 2005) Masry, Mark; Lipson, H.; Joaquim Armando Pires Jorge and Takeo Igarashi
This paper presents a freehand, sketch-based interface for Computed Aided Design (CAD) engineering design and finite element analysis. After a user sketches a two dimensional sketch consisting of connected straight and curved strokes, the sketch is processed by two optimization-based reconstruction algorithms that can reconstruct sketches of 3D objects made up of straight lines and planar curves. The proposed implementation allows certain types of objects with over 50 strokes to be reconstructed in interactive time. Following reconstruction, the structural properties of the 3D shape can be examined using finite element analysis. The object can quickly be modified using the pen-based interface according to the results of the analysis. The combination of a rapid, sketch-based design interface and finite element analysis allows users to iteratively design, analyze and modify 3D objects in an intuitive and flexible way.

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