Virtual Sculpting Research Articles

Freeform modelling using sweep differential equation with haptic interface

This paper presents the development of a virtual sculpting system and addresses the issues of interactive freeform solid modelling with haptic interface. A virtual reality (VR) approach is taken to make the developed system more intuitive and interactive. The virtual sculpting method is based on the metaphor of carving a primitive or imported solid model into a 3D freeform object. The geometric modelling is based on the sweep differential equation method to compute the boundary of the tool swept volume. The ray-casting method is used to perform Boolean operations to simulate the sculpting process. A new method of surface reconstruction from dexel data is presented. The PHANToM™ manipulator is used to provide the position and orientation data of the sculpting tool and also to provide haptic sensation to the user hand during the sculpting. An accuracy analysis is performed to determine the limitations on the sculpted geometric details.

Haptic sculpting of multi-resolution B-spline surfaces with shaped tools

In this paper, we first propose an implicit surface to B-spline surface haptic interface, which provides both force and torque feedback. We then present a new haptic sculpting system for B-spline surfaces with shaped tools of implicit surface. In the physical world, people touch or sculpt with their fingers or tools, instead of just manipulating points. Shaped virtual sculpting tools help users to relate the virtual modeling process to physical-world experience. Various novel haptic sculpting operations are developed to make the sculpting of B-spline surfaces more intuitive. Wavelet-based multi-resolution tools are provided to let modelers adjust the resolution of sculpture surfaces and thus the scale of deformation can be easily controlled. Moreover, sweep editing and 3D texture have been implemented by taking advantage of both the wavelet technique and haptic sculpting tools.

Virtual prototyping and manufacturing planning by using tri-dexel models and haptic force feedback

This paper presents a new method of using the tri-dexel volumetric models and a haptics force feedback for virtual prototyping and manufacturing planning. In the proposed method, the initial polyhedral surface model is converted to a tri-dexel volumetric model by using a depth-peeling dexelization algorithm. In the virtual prototyping process, the tri-dexel volumetric model is updated by the swept volume of a moving cutter via a haptic force feedback interface device. A collision detection algorithm is proposed for the virtual sculpting and the pencil-cut planning with real-time haptic force feedback to the users. Tool paths are generated for machining the virtual sculpted parts via the simulation and verification on a virtual CNC machine tool before they are actually machined. Computer implementation and practical examples are also presented in this paper. The proposed method enables the haptic-aided virtual prototyping and manufacturing planning of complex surface parts.

Deformable mesh for virtual shape sculpting

A novel, interactive virtual sculpting framework based upon a deformable mesh model generated by a self-organizing feature map (SOFM) is described in this paper. The three-dimensional lattice of the SOFM maintains the relative connectivity of neighbouring nodes in the hexahedral mesh as it transforms from the initial reference geometry into the desired shape. Material and dynamic properties are incorporated into the deformable mesh by treating surface and internal nodes as point masses connected by a network of springs. The initial SOFM mesh can be either retrieved from a library of primitive shapes, or created by automatically adapting the 3D mesh to fit selected surface points. Once the initial mesh has been generated, the designer reshapes the virtual object by introducing external forces to the nodal mesh. The process of virtual sculpting is analogous to hand moulding of clay in the physical world where the material mass remains constant. During sculpting, the dynamically changing mesh can be easily rendered in VRML for visualization in a virtual reality environment. The deformable mesh generator and shape-sculpting system are illustrated by reshaping solid meshes created from scanned human heads.

Surface Reconstruction for Interactive Modeling of Freeform Solids by Virtual Sculpting

This paper presents a new method for surface reconstruction from dexel data for virtual sculpting. This is part of our research efforts to develop a dexel model based sculpting system with the capability of interactive solid modeling with haptics interface. Dexel data are converted to a series of planar contours in parallel slices (i.e. cross sections). Then triangular meshes are created by connecting the contour points in adjacent slices. Examples are given to demonstrate the ability of the described method to convert from dexel data to triangular meshes for the viewing of a sculpted model in different directions.

Haptic B-spline Surface Sculpting with a Shaped Tool of Implicit Surface

AbstractIn this paper, we propose a new implicit to B-spline surface haptic interface and present a new haptic sculpting system for B-spline surfaces with a shaped implicit surface probe/tool. In the physical world, people touch or sculpt with their fingers or tools, instead of just manipulating points. A shaped virtual haptic probe/tool helps users to relate the virtual deformation process to their real life experience. Using the PHANToM haptic device, modellers can touch and explore the model with a shaped probe/tool and feel the physically realistic presence of virtual objects. Various basic haptic sculpting tools are developed to facilitate the deformation of B-spline surfaces. The tool-model interaction is surface-object in nature instead of traditional point-object style. This leads to more intuitive virtual sculpting paradigms, which may help introduce new modeling techniques.

Dexel-based force–torque rendering and volume updating for 5-DOF haptic product prototyping and virtual sculpting

This paper presents new techniques of Dexel-based force–torque rendering and volume-updating for haptic virtual sculpting of complex surfaces with a developed 5-DOF (degree of freedom) haptic interface. In the proposed methodology, 5-axis tool motion and analytical tool swept volume are formulated for updating the virtual stock material, which is represented with the Dexel volume model. Based on the tool motion analysis, a Dexel-based collision detection method and a force–torque feedback algorithm are proposed for virtual sculpting. A lab-built 5-DOF force–torque output haptic interface system is developed for the proposed haptic sculpting system. With the proposed methodology, a user can virtually sculpt a volume stock to get an intuitive design by using the haptic interface. From the haptic sculpting system, both the corresponding tool motion of the creative process and the sculpted model can be recorded and output. The output STL models of the haptic sculpting system can be processed for machining planning. Based on the proposed techniques, hardware and software implementation of the haptic sculpting system as well as the illustrative examples are also presented in this paper.

A Visibility Sphere Marching algorithm of constructing polyhedral models for haptic sculpting and product prototyping

This paper presents a Visibility Sphere Marching algorithm of constructing polyhedral models from Dexel volume models for haptic virtual sculpting. Dexel volume models are used as the in-process models representation during interactive modification in a haptic virtual sculpting system. The stock material represented in a Dexel volume model is sculpted into a designed model using a developed haptic sculpting system. The sculpted Dexel volume models are converted to polyhedral surface models in STL format by the proposed visibility sphere marching algorithm. The conversion turns out to be an interesting and challenging problem. The proposed visibility sphere marching algorithm consists of three sub-algorithms: (i) roof and floor covering, (ii) wall-building, and (iii) hole-filling algorithms. The polyhedral surface models converted from the Dexel volume models can then be input to and processed by available computer-aided manufacturing (CAM) or rapid prototyping systems. The presented technique can be used in virtual sculpting, CAD/CAM, numerically controlled machining verification and rapid prototyping.

Vector classification of SMD images

The localization of the components of an object near to a device before obtaining the real interaction is usually determined by means of a proximity measurement to the device of the object’s features. In order to do this efficiently, hierarchical decompositions are used, so that the features of the objects are classified into several types of cells, usually rectangular.In this paper we propose a solution based on the classification of a set of points situated on the device in a little-known spatial decomposition named tetra-tree. Using this type of spatial decomposition gives us several quantitative and qualitative properties that allow us a more realistic and intuitive visual interaction, as well as the possibility of selecting inaccessible components. These features could be used in virtual sculpting or accessibility tasks.In order to show these properties we have compared an interaction system based on tetra-trees to one based on octrees.

Vsculpt: a distributed virtual sculpting environment for collaborative design

A collaborative virtual sculpting system supports a team of geographically separated designers/engineers connected by networks to participate in designing three-dimensional (3D) virtual engineering tools or sculptures. It encourages international collaboration at a minimal cost. However, in order for the system to be useful, two factors need to be addressed: intuitiveness and real-time interaction. Although a lot of effort has been put into developing virtual sculpting environments, only limited work addresses collaborative virtual sculpting. This is because in order to support real-time collaborative virtual sculpting, many challenging issues need to be addressed. We propose a collaborative virtual sculpting framework, called VSculpt. Through adapting some techniques we developed earlier and integrating them with some techniques developed here, the proposed framework provides a real-time intuitive environment for collaborative design. In particular, it addresses issues on efficient rendering and transmission of deformable objects, intuitive object deformation using the CyberGlove and concurrent object deformation by multiple clients. We demonstrate and evaluate the performance of the proposed framework through a number of experiments.

Virtual Sculpting and Virtual Woodblock Printing by Model-Driven Scheme

本論文では，仮想彫刻に基づく仮想木版画の生成法と応用について解説する．提案法は芸術•工芸の模擬を目指した非写実的画像合成法(NPR) のひとつである．一般に絵画などを志向したNPR で用いられている技法は，(a) ABR: 生成外観を模擬したレンダリング手法，(b) PBR: 物理モデルに基づくレンダリング手法，に大別されるが，本論文で解説する仮想木版画は(b) PBR に基づくものである．まず仮想彫刻システムによって仮想版木が生成される．次いで仮想版木，仮想紙，仮想馬連，仮想絵の具により，仮想木版画画像が生成される．このように提案法は木版画の制作工程を重視したものであるため，生成画像は物理的な裏付けを持ち，外観上も良い結果を与えている．また，仮想木版画手法を用いた仮想浮世絵の知的符号化，及びそれを通した仮想彫刻と仮想木版画の問題点と今後の課題についても言及する．

Virtual 3D Sculpting

This paper presents a virtual sculpting method for interactive 3D object deformation. The method is based on the use of an electronic glove. A parametric control hand surface defined by an open-uniform B-spline tensor product surface is first created to model the hand gesture. The geometric attributes of the object in the Euclidean 3D space are then mapped to the parametric domain of the control hand surface through a ray projection method. By maintaining the distances between the mapped pairs, change of hand gesture can be efficiently transferred to control the deformation of the object. Copyright © 2000 John Wiley & Sons, Ltd.

An Interactive Designing System with Virtual Sculpting and Virtual Woodcut Printing

In this paper, we propose an interactive designing method and a system based on it to create 3D objects and 2D images. This system consists of two subsystems for virtual sculpting to create a 3D shape and virtual printing to produce a picture with a printing block. In the virtual sculpting subsystem, a user can form solid objects with curved surfaces as if sculpting them. The user operates virtual chisels, and can remove or attach arbitrary shapes of ellipsoids or cubes from or to the workpiece. A 3D object generated by virtual sculpting looks like a real wooden sculpture. If using a board as a workpiece, a user can generate a virtual printing block. In the virtual printing subsystem, a user can synthesize a woodcut printing image from the virtual printing block mentioned above, a virtual paper sheet, and a printing brush. The user can synthesize a realistic woodcut print with a procedure similar to the actual woodcut printing.

Virtual sculpting and virtual woodcut printing

Virtual sculpting and virtual woodcut printing

The ThingWorld modeling system: virtual sculpting by modal forces

We describe a real-time solid modeling system that is based on the physical analogy of forming clay by applying forces. The system is implemented by simulating real materials as they react to user-supplied forces. Unlike other physically-based modeling approaches, the Thingworld system allows the user to restrict forming action to simple global deformations during the initial "roughing in" phase of modeling, and then later concern themselves with detailing. The Thingworld system also allows users to automatically model existing objects by using measurements taken from the object's surface. These measurements are used to generate artificial forces that mold the computer model much as a human would mold a clay model. Timed examples for constructing solid models are shown.