Sketch based interfaces and modeling pdf

Two experiments one in architecture and one in product design based on ergonomics theory are conducted and intend to question some of these more » The Port Zeeland experiment examines how 20 novices perceive and copy a blurred architectural sketch, which provides clues for a sketch interpretation system. The "Tragere" experiment studies how 12 professional product designers, some of whom are "idea generators" and others "idea pursuers," perceive, recognize, and handle a design sketch.

The results take a designer's point of view in assessing the timing and value of sketch assistance in product design.

The quantitative data analysis provides rich clues about when, why and how product sketches should be supported. Terrain Sketching [37] is a work that uses The adding detail is intrinsically linked to the surface sketches to define the landform macro-structure.

After, the representation. For example, we can edit details using nor- application uses some procedural methods to synthesize a mals [42] Figure 13a. Or, we can add some features to the realistic geometry Figure Figure As mentioned, sketching is a very good way to convey an 13b. Gingold and Zorin [43] shows a editing method based idea with few strokes. Thus, we should not expect a wealth on sketches that represent shading on surface Figure Therefore, a character- Olsen et al [44] show an example of editing details in a istic of sketch-based modeling is generating objects with subdivision surface Figure They project the sketch on coarse geometry.

Even with this set of different techniques the mesh, they apply an adaptive subdivision based on the for building 3D graphics objects from sketches, it is still curve. So, it is created a feature in the object. We can to deformate the surface or blend two pieces. Moreover, there are applications that model objects of a Wang [45] shows how blending two surfaces smoothly. When the The aforementioned operations do not change the struc- modeled object classes is known it can compensate for the ture of the previously modeled object.

But, some operations limited information contained in the sketch with data known modify the structure locally or globally. A simple example is by application a priori. In such cases, the sketch is used to determine the structural elements of the model, while the details are inferred by the application. We can cite specific classes of modeled object: hair [38] Figure 16a , trees [39] Figure 16b and flowers [40]. Creating a geometric model from sketches is not a simple task.

Figure 17 shows an example of a sketch that we can not yet generate a 3D environment only by interpreting the model curves. It is only possible from simplistic construction techniques. Thus, to refine the object it is necessary to edit it. Editing techniques will be presented in the next section.

Example of a sketch difficult to create a 3D model. Shading-based surface editing. Detail adding in meshes. Local structural editing. Model Representation resizing an object Figure 21b.

In this case, the application needs to interpret the meaning of the operation on the full In this section we will describe some methods to rep- object global deformation and not just changing the faces resent the geometric support of a graphic object. We will containing the manipulated edge local deformation. We can divide the surface iWIRES [46] is another application that interprets the representations in two categories: parametric and implicit.

The Parametric surfaces is a widely used object representation. Then, we This consists in defining an atlas for the modeled surface. This deformation is interpreted and propagated whose images cover the surface. It can have interesting throughout the object Figure 21d. Normally these are based are examples of parametric representations, widely used in on structural curves.

Cherlin et al [47] show a deformation modeling applications. These techniques have been widely way modifying the object medial axis Figure 21e. Nealen et al [22] Implicit surfaces are obtained from the solution of an show a method to apply local structural editing of meshes equation.

This representation facilitates operations such as conti- presented by Kho et al [48]. After modeling, they construct nence test and boolean operations. But, it hinders perform the medial axis of the object. It enables deforming the object operations such as smoothing, adding features and structural locally through a partial deformation of the medial axis. This or punctual deformation. One type of implicit surface used deformation is done through a sketch determining the new in modeling is isosurface.

Both implicit and parametric objects are commonly trans- In this work, we focus on 3D modeling. Although, there formed into meshes to aid rendering. Graphic hardwares are sketch-based editing images works [49] Figure Furthermore, there are several results that work with meshes. These representations are Throughout this section, we presented some editing oper- widely used in modeling applications, because they allow ations on the model.

Similar to creation techniques, editing modeling objects of any topology. On the other hand, it is techniques are strongly tied to the object representation. In more complicated to perform editing operations on meshes. Both operations and repre- sentation techniques have its positive and negative aspects. Thus, it is not possible to determine a set of operations and a specific representation to produce good results for all mod- eling purposes. These choices depend on the project.

In the next section, we present some challenges and possibilities on SBIM, highlighting some choices made in some works. Sketch-based image deformation. We can classify the development decisions in SBIM into two categories: modeling and user interaction. The modeling decisions refers to the choice of modeling methods creation Figure In this section, we will discuss the decisions regarding user-application inter- Multitouch devices usually have a lower precision, be- action, addressing the possibilities that arise from different cause the input interface may have low resolution, or because device acquisitions and analysing interface aspects.

The precision decrease can hinder the detail adding, for user-application interaction have evolved. We can differ example. Another disadvantage is it is susceptible to noise. In this section, we and treated through post-processing, they may cause some will analyze some data acquisition devices highlighting how undesired effects, or at least, require special attention. An application can use more than one type of acquisition The mouse and keyboard are the most known and used devices through a mapping of the captured information.

By moving the mouse, we can obtain a position set However, some informations are device specific. Thus, an of the trace and we can know if any button was pressed or important decision is which devices are supported. If we if the scroll was turned.

With the keyboard, it is possible choose a specific type, we can avail their resources and to trigger events related to pressing one or more keys. These events have been shown sufficient for developing of The interface objects are another relevant aspects of the modeling applications. However, devices such as Tablet and interaction. The interface paradigm affects directly in the tangible interfaces let we capture information that can be inference of which operation the system should execute used in modeling, making it more natural.

Tablets allow capture of the position and the inclination The interfaces of modeling applications like Maya, of the pen, beyond the pressure exerted by the user doing Blender and autoCAD are complicated. Moreover, this in- the drawing.

Furthermore, the input interface is the same as terfaces lets we easily add a functionality adding a widget the output, which make the drawing process more natural. Moreover, the user starts a specific action once he This allows that the location where the user touches the pen activates a widget, without ambiguity. Accomplishing this in to be mapped onto the screen in the same position of the gesture-based systems remains a challenge.

This is different from what happens with the mouse. Another challenge is known as Self-Disclosure. This prob- People prefer drawing with a pen than with a mouse. In lem consists in fact of in purely gesture-oriented interface applications that use the mouse, the users adjust themselves a user does not know which gestures are significant to the to the system, making precise drawings. However, drawing system. Novice users find it easier to trying the widgets, reading labels and looking at icons.

So use a Tablet, making more accurate and faster strokes. Multitouch with sketch-based interfaces is a compromise in the choice interfaces allow the user to interact with the system using of interface objects.

The functionalities should be easily ac- his fingers or tangible objects which enables to create a cessible without too many widgets that pollute the interface immersive and natural system. In this device the input and and hinder the learning. Another challenge is to propose output are on the same interface, similar to the Tablet. The interaction using multiple fingers allow performing We can classify an object interface in an SBIM application operations that with just one cursor would be more difficult in three categories: widgets of window, of scene and of or even impossible.

For modeling, this feature facilitates the object. The widgets of window are application objects that drawing of curves with symmetry and parallelism. Another are outside of the modeling canvas, used to specify a state advantage of using the finger is to avail the maximum or operation in the application.

Widgets of scene are objects efficiency of the user motor control. Widgets of objects are elements that angle the rotation relatives to the coordinate system of the operate on modeled objects.

Each of these widgets can be table. A fiducial can be used to trigger events or evoke some modeled taking into account four aspects: representation, widgets such as menus, for example. Interface Objects. In purely gesture-based interfaces, the greatest challenge as it is captured. It can be made on existing objects or on is recognizing a gesture to associate it with an operation. Tsang et al [26] presented a work that uses Existing solutions relate to very specific gestures.

The use these planes for modeling Figure 23b. This support surface of gestures can replace the use of a set of widgtes. On the can have a more complicated geometry enabling creation of other hand, if the system accomplish many operations there a convenient environment space for the sketch. Beyond these interface elements we can senting all possible operations and let the user choose. This have mechanisms such as learning from the user, querying type of interface is known as a suggestive interface.

Magic information in a database, multiple remote users, etc. Canvas [34] Figure 23c is an example of application that All resources mentioned in this section can be used on a shows a suggestive interface. Thus, an interface should be clean, easy to notations. These annotations can be used in the sketch use and learn, accessible functionalities and natural. These interpretation. Sketch2Photo [50] Figure 23a is an example goals must be analyzed to define a compromise between of application that uses annotations.

Another resource is the application trying to infer future V. Based on the architecture proposed in this paper, we This feature is called prediction, and it can accelerate the developed a prototype toolkit with a set of generic features modeling process, and ensure that the object maintains some that can be used in different SBIM applications. The use of elements, such as suggestion, prediction and VI. The of key trends and features present in SBIM applications.

These tasks exploit the ability of the gestures and WIMP with an unpolluted interface because sketch to quickly convey an idea. In modeling, sketching the menu displays only the options that the user can choose is useful to draw contours, or to highlight a feature of among the last gesture executed. Another feature, which the object. Furthermore, the use of sketch in a modeling facilitates the user-application interaction, is to highlight the application is an intuitive resource because it is similar to selected elements eg vertices, edges, faces, objects, or some the act of making a drawing on paper.

When a designer semantic to each operation. Some examples are applications is making a drawing, he usually uses some constructive that use beautification; or applications that perform global technique, based on specific curves, such as silhouette, deformation based on few traces.

Another modeling trend is suggestive contours and constructive curves. Some of these to make structural deformation preserving details. One is the suggestions facilitating the modeling and resolve ambigui- screen plane.

Once the user start modeling the sketch points ties. The use of predictions also follows the trend of inferring should be transformed to the coordinate system of the scene. On one hand, interpreting a sketch is not a simple task tions of modeling using sketches are interesting research and ambiguity problems may be encountered.

On the other topics in SBIM. Despite the challenges listed, applications hand, by dominating this procedure, we will be able to create based on sketches have shown a trend in modeling. In this cleaner interfaces with fewer Widgets and therefore faster text, we presented several examples of applications, with to learn and easier to use. Although in this work we have some interesting results, and several possibilities that can be concentrated only in specific concepts and features related merged to build a robust modeling system.

We can cite games, media organizers and We would like to thank the CNPq, for funding the viewers, story board, smart boards, image manipulation, etc. In interfaces based solely on gestures it is difficult to add many functionalities, be- [1] I. This problem can be attacked interpreting the [2] R. Zeleznik, K. Herndon, and J. Although the major motivation of SBIM is to create an application that resembles the way an artist makes a [3] T. Igarashi and J.

Usually the applications have its own peculiarities [4] T. Igarashi, S. Matsuoka, and H. This reduces the sense of immersion and naturalness with [5] R. Schmidt, B. Wyvill, M. Sousa, and J. Thus, one of sketch-based solid modeling with blobtrees. Nealen, T. Igarashi, O.

Sorkine, and M. Although we have shown sketch-based techniques for modeling and deformation, the vast majority [7] L. Olsen, F. Samavati, M. Moreover, many artists while drawing using other techniques such as shading, oversketching, dotted, etc.

To [8] M. Cook and A. The major advantage of using a sketch is the ease of [9] P. Company, A. Piquera, M. Contero, and F. This is due to the fact that on geometrical reconstruction as a core technology to sketch- people can easily interpret a sketch and associate to it based modeling. Use sketch in the constructive process involves to interpret it and associate it [10] J.

Gomes and L. Another major [11] F. Samavati and R. Another SBIM challenge is creating models with high quality, as in traditional modeling applications. A resource [12] T. Presents the first unified overview of sketch-based interfaces and modeling Discusses the state of the art of the field Provides contributions from an international selection of experts Includes supplementary material: sn.

Front Matter Pages Faramarz F. Samavati, Luke Olsen, Joaquim A. Pages Pen-based Interfaces for Engineering and Education. Flexible Parts-based Sketch Recognition. Sketch-based Retrieval of Vector Drawings. Manuel J.