机械英文翻译搅拌机.docx

1、机械英文翻译搅拌机机械英文文献翻译-延长搅拌机机械英文文献翻译-延长搅拌机HAVE2007 - IEEE International Workshop onHaptic Audio Visual Environments and their ApplicationsOttawa, Canada 12-14 October 2007Extending Blender: Development of a Haptic Authoring ToolSheldon Andrews, Mohamad Eid2, Atif Alamri2, and Abdulmotaleb El Saddik2Multi

2、media Communications Research Laboratory - MCRLabSchool ofInformation Technology and Engineering - University ofOttawaOttawa, Ontario, KIN 6N5, CanadasandrO71site. uottawa. ca, 2 teid, atifW abed mcrlab. uottawa. CaAbstract -In this paper, we present our work to extend a well known 3D graphic modele

3、r - Blender - to support haptic modeling and rendering. The extension tool is named HAMLAT (Haptic Application Markup Language Authoring Tool). We describe the modifications and additions to the Blender source code which have been used to create HAMLAT Furthermore, we present and discuss the design

4、decisions used when developing HAMLAT, and also an implementation road map which describes the changes to the Blender source code. Finally, we concludewith discussion of our future development and research avenues.Keywords - Haptics, HAML, Graphic Modelers, Blender, Virtual Environments.I. INTRODUCT

5、IONA. MotivationThe increasing adoption of haptic modality in human-computer interaction paradigms has led to a huge demand for new tools that help novice users to author and edit haptic applications. Currently, the haptic application development process is a time consuming experience that requires

6、programming expertise. The complexity of haptic applications development rises from the fact that the haptic application components (such as the haptic API, the device, the haptic rendering algorithms, etc.) need to interact with the graphic components in order to achieve synchronicity.Additionally,

7、 there is a lack of application portability as the application is tightly coupled to a specific device that necessitates the use of its corresponding API. Therefore, device and API heterogeneity lead to the fragmentation and disorientation of both researchers and developers. In view of all these con

8、siderations, there is a clear need for an authoring tool that can build haptic applications while hiding programming details from the application modeler (such as API, device, or virtual model).This paper describes the technical development of the Haptic Application Markup Language Authoring Tool (H

9、AMLAT). It is intended to explain the design decisions used for developing HAMLAT and also provides an implementation road map, describing the source code of the project.B. BlenderHAMLAT is based on the Blender 1 software suite, which is an open-source 3D modeling package with a rich feature set. It

10、 has a sophisticated user interface which isnoted for its efficiency and flexibility, as well as its supports for multiple file formats, physics engine, modem computer graphic rendering and many other features.Because of Blenders open architecture and supportive community base, it was selected as th

11、e platform of choice for development of HAMLAT. The open-source nature of Blender means HAMLAT can easily leverage its existing functionality and focus on integrating haptic features which make it a complete hapto-visual modeling tool, since developing a 3D modeling platform from scratch requires co

12、nsiderable development time and expertise in order to reach the level of code into the HAMLAT source tree.HAMLAT builds on existing Blender components, such as the user-interface and editing tools, by adding new components which focus on the representation, modification, and rendering of haptic prop

13、erties of objectsin a 3D scene. By using Blender as the basis for HAMLAT, we hope to develop a 3D haptic modeling toolwhich has the maturity and features of Blender combinedwith the novelty of haptic rendering.At the time of writing, HAMLAT is based on Blender version 2.43 source code.C. Project Goa

14、lsAs previously stated, the overall goal for the HAMLAT project is to produce a polished software application which combines the features of a modem graphic modeling tool with haptic rendering techniques. HAMLAT has the look and feel of a 3D graphical modeling package, but with the addition of featu

15、res such as haptic rendering and haptic property descriptors. This allows artists, modelers, and developers to generate realistic 3D hapto-visual virtual environments.A high-level block diagram of HAMLAT is shown in Figure 1. It illustrates the flow of data in the haptic modeling. HAMLAT assists the

16、 modeler, or application developer, in building hapto-visual applications which may be stored in a database for later retrieval by another haptic application. By hapto-visual application we refer to any software which displays a 3D scene both visually and haptically to a user in a virtual setting. A

17、n XML file format, called HAML 2, is used to describe the 3D scenes and store the hapto-visual environments built by a modeler for later playback to an end user.Traditionally, building hapto-visual environments has required a strong technical and programming background. The task of haptically render

18、ing a 3D scene is tedious 1108since haptic properties must be assigned to individual objects in the scene and currently there are few high-level tools for accomplishing this task. HAMLAT bridges this gap by integrating into the HAML framework and delivering a complete solution for development of hap

19、to- visual applications requiring no programming knowledge.The remainder of the paper is organized as follows: in Section 2, we present the proposed architecture extensions and discuss design constraints. Section 3 describes the implementation details and how haptic properties are added and rendered

20、 within the Blender framework. In Section 4 we discuss related issues and future work avenues.II. SYSTEM OVERVIEW AND ARCHITECTUREThe Blender design philosophy is based on three main tasks: data storage, editing, and visualization. According to the legacy documentation 3, it follows a data- visualiz

21、e-edit development cycle for the 3D modeling pipe line. A 3D scene is represented using data structures within the Blender architecture. The modeler views the scene, makes changes using the editing interface which directly modifies the underlying data structures, and then the cycle repeats.To better

22、 understand this development cycle, consider the representation of a 3D object in Blender. A 3D object may be represented by an array of vertices which havebeen organized as a polygonal mesh. Users may choose to operate on any subset of this data set. Editing tasks may include operations to rotate,

23、scale, and translate thevertices, or perhaps a re-meshing algorithm to cleanup redundant vertices and transform from a quad to a triangle topology. The data is visualized using a graphical 3D renderer which is capable of displaying the object as a wireframe or as a shaded, solid surface. The visuali

24、zation is necessary in order to see the effects of editing on the data. In a nutshell, this example defines the design philosophy behind Blenders architecture.In Blender, data is organized as a series of lists and base data types are combined with links between items in each list, creating complex s

25、cenes from simple structures.This allows data elements in each list to be reused, thus reducing the overall storage requirements. For example, a mesh may be linked by multiple scene objects, but the position and orientation may change for each object and the topology of the mesh remains the same. A

26、diagram illustrating the organization of data structures and reuse of scene elements is shown in Figure 2. A scene object links to three objects, each of which link to two polygonal meshes. The meshes also share a common material property. The entire scene is rendered on one of several screens, whic

27、h visualizes the scene.We adopt the Blender design approach for our authoring tool. The data structures which are used to represent objects in a 3D scene have been augmented to include fields for haptic properties (e.g., stiffness, damping); user interface components (e.g., button panels) which allo

28、w the modeler to change object properties have also been updated to include support for modifying the haptic properties of an object. Additionally, an interactive hapto-visual renderer has been implemented to display the3D scene graphically and haptically, providing the modeler or artist with immedi

29、ate feedback about the changes they make to the scene. in the current version of the HAMLAT. the modifications to the Blender framework include: data structures for representing haptic properties, an editing interface for modifying haptic properties, an external renderer for displaying and previewin

30、g haptically enabled scenes, scripts which allow scenes to be imported/exported in the HAML file format.A class diagram outlining the changes to the Blender ramework is shown in Figure 3. Components which are ertinent to HAMLAT are shaded in gray. HAMLAT builds on existing Blender sub-systems by ext

31、ending them or haptic modeling purposes. Data structures for representing object geometry and graphical rendering areaugmented to include field which encompass the tactile properties necessary for haptic rendering.To allow the user to modify haptic properties GUI Components are integrated as part of

32、 the Blender editing panels. The operations triggered by these componentsoperate directly on the d ata structures used for representing hatic cues and may be considered part of the editing step of the Blender design cycle.Similarly to the built-in graphical renderer, HAMLAT uses a custom rendlerer for displaying 3Ds scenes grphcal and haptcall, an is ineedn of the Blender renderer. This component is developed independently since haptical and graphical rendering must be performed simultaneously and synchronously. A simulation loop is used to update haptic rend