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.

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.

Automatic extraction of free-form surface features (FFSFs)

2012 ◽  
Vol 44 (2) ◽  
pp. 99-112 ◽  
Author(s):  
Ravi Kumar Gupta ◽  
Balan Gurumoorthy
Keyword(s):  
Free Form ◽  
Automatic Extraction ◽  
Surface Features ◽  
Free Form Surface

Free-Form Surface Design in a Virtual Reality Environment

1999 ◽  
Author(s):  
Tushar Dani ◽  
Lin Wang ◽  
Rajit Gadh
Keyword(s):  
Virtual Reality ◽  
Free Form ◽  
Design System ◽  
Virtual Design ◽  
Surface Design ◽  
Surface Features ◽  
University Of Wisconsin ◽  
Free Form Surface ◽  
The University ◽  
Future Work

Abstract This paper presents an intuitive and easy-to-use Virtual Reality (VR)-based interface for free-form surface modeling. This work represents further enhancements to the VR-based parametric conceptual shape modeler (COVIRDS – COnceptual VIRtual Design System) currently being developed at the I-CARVE LAB at the University of Wisconsin-Madison. The current research utilizes an intuitive voice and hand input interface to allow editing of NURBS based free-form surface models. The editing scheme allows the designer to utilize higher level ‘primitive’ surface features, in deforming the free-form shape. In addition, interactively specified constraints allow constrained re-location of these surface features giving the designer additional flexibility in designing relatively complex free-form models. Preliminary results based on a prototypical implementation show that the VR-based interface allows free-form models to be created and edited in a much more intuitive way than is possible in conventional CAD systems. Future work will focus on improving the modeling capabilities of the system by integration with a conventional solid/surface modeler.

scholarly journals SPPD: A Novel Reassembly Method for 3D Terracotta Warrior Fragments Based on Fracture Surface Information

2021 ◽  
Vol 10 (8) ◽  
pp. 525
Author(s):  
Wenmin Yao ◽  
Tong Chu ◽  
Wenlong Tang ◽  
Jingyu Wang ◽  
Xin Cao ◽  
...  
Keyword(s):  
Fracture Surface ◽  
Principal Component ◽  
Point Clouds ◽  
Three Dimension ◽  
Registration Method ◽  
Series Of Experiments ◽  
Coarse To Fine ◽  
Fine Registration ◽  
Common Situation ◽  
Better Than

As one of China′s most precious cultural relics, the excavation and protection of the Terracotta Warriors pose significant challenges to archaeologists. A fairly common situation in the excavation is that the Terracotta Warriors are mostly found in the form of fragments, and manual reassembly among numerous fragments is laborious and time-consuming. This work presents a fracture-surface-based reassembling method, which is composed of SiamesePointNet, principal component analysis (PCA), and deep closest point (DCP), and is named SPPD. Firstly, SiamesePointNet is proposed to determine whether a pair of point clouds of 3D Terracotta Warrior fragments can be reassembled. Then, a coarse-to-fine registration method based on PCA and DCP is proposed to register the two fragments into a reassembled one. The above two steps iterate until the termination condition is met. A series of experiments on real-world examples are conducted, and the results demonstrate that the proposed method performs better than the conventional reassembling methods. We hope this work can provide a valuable tool for the virtual restoration of three-dimension cultural heritage artifacts.

A Golay3 sparse aperture optical system of primary mirror with free-form surface

2021 ◽  
Vol 28 (1) ◽  
pp. 113-118
Author(s):  
Bin Chen ◽  
Quanying Wu ◽  
Junliu Fan
Keyword(s):  
Optical System ◽  
Free Form ◽  
Primary Mirror ◽  
Sparse Aperture ◽  
Free Form Surface

Tool Path Generation for Five-Axis Controlled Machining of Free-Form Surface Using Barrel Tool: Control of Contact Point on Cutting Edge

2020 ◽  
Author(s):  
Tomonobu Suzuki ◽  
Koichi Morishige
Keyword(s):  
Tool Path ◽  
Contact Point ◽  
Cutting Edge ◽  
Free Form ◽  
End Mill ◽  
Ball End Mill ◽  
Surface Machining ◽  
Free Form Surface ◽  
The Cost ◽  
Five Axis

Abstract This study aimed to improve the efficiency of free-form surface machining by using a five-axis controlled machine tool and a barrel tool. The barrel tool has cutting edges, with curvature smaller than the radius, increasing the pick feed width compared with a conventional ball end mill of the same tool radius. As a result, the machining efficiency can be improved; however, the cost of the barrel tool is high and difficult to reground. In this study, a method to obtain the cutting points that make the cusp height below the target value is proposed. Moreover, a method to improve the tool life by continuously and uniformly changing the contact point on the cutting edge is proposed. The usefulness of the developed method is confirmed through machining simulations.

Application of Convex Hull for Tool Interference Avoidance in 5-Axis CNC Machining

1996 ◽  
Author(s):  
Yuan-Shin Lee ◽  
Tien-Chien Chang
Keyword(s):  
Convex Hull ◽  
Tool Path ◽  
Correction Method ◽  
Nc Machining ◽  
Cnc Machining ◽  
Free Form ◽  
Interference Avoidance ◽  
Tool Interference ◽  
Free Form Surface ◽  
Free Form Surfaces

Abstract In this paper, a methodology of applying convex hull property in solving the tool interference problem is presented for 5-axis NC machining of free-form surfaces. Instead of exhausted point-by-point checking for possible tool interference, a quick checking can be done by using the convex hull constructed from the control polygon of free-form surface modeling. Global tool interference in 5-axis NC machining is detected using the convex hull of the free-form surface. A correction method for removing tool interference has also been developed to generate correct tool path for 5-axis NC machining. The inter-surface tool interference can be avoided by using the developed technique.

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