Creation and Manipulation of Complex Displacement Features During the Conceptual Phase of Design

1996 ◽  
Author(s):  
P. A. van Elsas ◽  
J. S. M. Vergeest
Keyword(s):  
Boundary Conditions ◽  
Surface Feature ◽  
Free Form ◽  
Shape Design ◽  
Surface Model ◽  
Test Results ◽  
Base Surface ◽  
Feature Design ◽  
Data Explosion ◽  
Free Form Surface

Abstract Surface feature design is not well supported by contemporary free form surface modelers. For one type of surface feature, the displacement feature, it is shown that intuitive controls can be defined for its design. A method is described that, given a surface model, allows a designer to create and manipulate displacement features. The method uses numerically stable calculations, and feedback can be obtained within tenths of a second, allowing the designer to employ the different controls with unprecedented flexibility. The algorithm does not use refinement techniques, that generally lead to data explosion. The transition geometry, connecting a base surface to a displaced region, is found explicitly. Cross-boundary smoothness is dealt with automatically, leaving the designer to concentrate on the design, instead of having to deal with mathematical boundary conditions. Early test results indicate that interactive support is possible, thus making this a useful tool for conceptual shape design.

Multiple-Points Constraints Based Deformation for Free-Form Surfaces

1999 ◽  
Author(s):  
J. M. Zheng ◽  
K. W. Chan ◽  
I. Gibson
Keyword(s):  
Surface Deformation ◽  
Single Point ◽  
Displacement Function ◽  
Surface Shape ◽  
Free Form ◽  
Surface Model ◽  
Deformation Method ◽  
Multiple Points ◽  
Free Form Surface ◽  
Free Form Surfaces

Abstract There is an increasing demand in the conceptual design for more intuitive methods for creating and modifying free-form curves and surfaces in CAD modeling systems. The methods should be based not only on the change of the mathematical parameters but also on the user’s specified constraints and shapes. This paper presents a new surface representation model for free-form surface deformation representation. The model is a combination of two functions: a displacement function and a function for representing an existing NURBS surface called parent surface. Based on the surface model, the authors develop two deformation methods which are named SingleDef (Single-point constraint based deformation method), and MultiDef (Multiple-points constraints based deformation method). The techniques for free-form surface deformation allow conceptual designer to modify a parent surface by directly applying point constraints to the parent surface. The deformation methods are implemented and taken in an experimental CAD system. The results show that the designer can easily and intuitively control the surface shape.

Study on automated non-contact measurement of 3-D edge profile for free form surface model

2000 ◽  
Vol 2000.3 (0) ◽  
pp. 541-542
Author(s):  
Yasuhiro TAKAYA ◽  
Seojoon LEE ◽  
Satoru TAKAHASHI ◽  
Takashi MIYOSHI
Keyword(s):  
Free Form ◽  
Surface Model ◽  
Contact Measurement ◽  
Edge Profile ◽  
Free Form Surface

scholarly journals Reverse Engineering of Free-Form Surface Based on the Closed-Loop Theory

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Xue Ming He ◽  
Jun Fei He ◽  
Mei Ping Wu ◽  
Rong Zhang ◽  
Xiao Gang Ji
Keyword(s):  
Reverse Engineering ◽  
Point Cloud ◽  
Closed Loop ◽  
Free Form ◽  
Surface Model ◽  
Accurate Model ◽  
Check Points ◽  
Adaptive Measurement ◽  
Free Form Surface ◽  
Free Form Surfaces

To seek better methods of measurement and more accurate model of reconstruction in the field of reverse engineering has been the focus of researchers. Based on this, a new method of adaptive measurement, real-time reconstruction, and online evaluation of free-form surface was presented in this paper. The coordinates and vectors of the prediction points are calculated according to a Bézier curve which is fitted by measured points. Final measured point cloud distribution is in agreement with the geometric characteristics of the free-form surfaces. Fitting the point cloud to a surface model by the nonuniform B-spline method, extracting some check points from the surface models based on grids and a feature on the surface, review the location of these check points on the surface with CMM and evaluate the model, and then update the surface model to meet the accuracy. Integrated measurement, reconstruction, and evaluation, with the closed-loop reverse process, established an accurate model. The results of example show that the measuring points are distributed over the surface according to curvature, and the reconstruction model can be completely expressed with micron level. Meanwhile, measurement, reconstruction and evaluation are integrated in forms of closed-loop reverse system.

Free Form Surface Reconstruction Method Based on LS-SVM

2011 ◽  
Vol 308-310 ◽  
pp. 280-283
Author(s):  
Fu Zhong Wu
Keyword(s):  
Surface Reconstruction ◽  
Approximation Error ◽  
Engineering Application ◽  
Least Square ◽  
Free Form ◽  
Support Vector ◽  
Surface Model ◽  
Reconstruction Method ◽  
Svm Model ◽  
Free Form Surface

A free form surface reconstruction method based on least square support vector regression is presented. Firstly in order to eliminate noise points, some sample points are chosen from the measured data to construct LS-SVM model. Thus a LS-SVM model to approximate the measured points is obtained. And the distribution probability of the approximation error is figured out. In result, the noise points are eliminated when their error probability is less than the specified threshold value. Then the boundary points are extracted. Lastly the surface model is reconstructed by use of the measured points from which noise points have been eliminated. The results indicate that the reconstruction precision can satisfy the demands of engineering application.

Study on CAD Modeling Based on Feature Extraction

2011 ◽  
Vol 308-310 ◽  
pp. 83-87
Author(s):  
Xiang Jun Hui ◽  
Ping Cheng
Keyword(s):  
Feature Extraction ◽  
Feature Recognition ◽  
Gauss Curvature ◽  
Surface Feature ◽  
Free Form ◽  
Feature Points ◽  
Quadric Surface ◽  
Cloud Data ◽  
Section Data ◽  
Free Form Surface

In this paper , key techniques of feature extraction in reverse engineering is studied. First use a method to extract the feature points from scattered points based on Gauss curvature extreme point. Use these feature points to make cloud data segmentation. Then quadric surface feature and free-form surface feature can be separated. The quadric surface feature can be fitted by quadric surface parameter equation with LSM directly. However the free-form surface feature should be extracted based on section feature recognition. This method has several steps: First ,a adaptive slicing algorithm is used to get section data from point data . Then feature points from section data is extracted. And these feature points are regarded as the gist to recognize section feature. When the section feature is recognized, they should be fitted with LSM, and then skinning method is used to reconstruct free-form surface modeling.

Coarse-to-Fine Extraction of Free-Form Surface Features

2015 ◽  
Vol 15 (1) ◽  
Author(s):  
Bing Yi ◽  
Zhenyu Liu ◽  
Guifang Duan ◽  
Jianrong Tan
Keyword(s):  
Principal Component ◽  
Free Form ◽  
Base Surface ◽  
Surface Features ◽  
Height Functions ◽  
Key Issues ◽  
Free Form Surface ◽  
Improved Performance ◽  
Laplacian Smoothing ◽  
Coarse To Fine

Free-form surface features (FFSFs) extraction is one of the key issues for redesigning and reediting the surface models exported from commercial software or reconstructed by reverse engineering. In this paper, a coarse-to-fine method is proposed to robustly extract the FFSFs. First, by iterative Laplacian smoothing, a set of height functions are generated, and principal component analysis (PCA) is employed to obtain the appropriate iteration number for the feature field extraction that is then accomplished by the Gaussian mix model (GMM) with a high segmentation threshold. Second, based on the feature field, an adaptive smooth ratio for each vertex is proposed for Laplacian smoothing, which is implemented to generate a precise base surface. Thereby, with the base surface, the FFSFs can be easily extracted by using the GMM. The empirical results illustrate that the proposed method yields improved performance for extracting FFSFs compared with conventional methods.

A User Interface for Free-Form Shape Design at the Responsive Workbench

2004 ◽  
Vol 4 (3) ◽  
pp. 178-185 ◽  
Author(s):  
Gerold Wesche
Keyword(s):  
User Interface ◽  
Virtual Environment ◽  
Conceptual Design ◽  
Free Form ◽  
Shape Design ◽  
Input Devices ◽  
3D Environment ◽  
Surface Models ◽  
Interaction Scheme ◽  
Free Form Surface

This paper presents a virtual environment based user interface for the conceptual design of free form surface models from scratch. The user performs sketching and elaboration directly within a projection-based, table-like environment. He uses head-tracked stereo glasses and simple input devices. We describe user interface components for creation, manipulation, and application control, which were specifically designed for use in a 3D environment. These components are part of a two-handed interaction scheme. In our modeling approach, the user draws curves and constructs a curve network that forms the skeleton of the surface. Automatic surfacing methods generate shapes that correspond to the outlined boundary, thus freeing the designer from specifying all surface parameters by hand. We demonstrate how the use of a virtual environment benefits such creation and manipulation tasks.

Experimental Assessment for Examination of Curves and Surfaces by Auditory Sense

1997 ◽  
Vol 9 (6) ◽  
pp. 434-438
Author(s):  
Hidetomo Takahashi ◽  
◽  
Satoshi Kanai ◽  
Keyword(s):  
Acoustic Waves ◽  
Experimental System ◽  
Free Form ◽  
Surface Model ◽  
Geometric Information ◽  
Experimental Assessment ◽  
Curves And Surfaces ◽  
Surface Models ◽  
Auditory Sense ◽  
Free Form Surface

The purpose of this research is to assess the ability of the auditory sense to examine curves and free-form surface models in order to verify their appearances. In this paper, the authors will first show how to display a curve and a surface model using an acoustic wave, i.e., the information about curves and surfaces that is needed, the kinds of acoustic waves that should be displayed, and how to relate the geometric information from curves or surfaces to the acoustic waves that are to be displayed. Next, the authors will discuss their newly developed experimental system. Finally, the ability of the auditory sense to examine curves and surfaces will be assessed experimentally. It will be demonstrated that the auditory sense can examine curves and surfaces.

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