Interval Method for Interrogation of Implicit Solid Models

2000 ◽  
Author(s):  
Jack Chang ◽  
Mark Ganter ◽  
Duane Storti
Keyword(s):  
Computer Aided Design ◽  
Boundary Representation ◽  
Free Form ◽  
Solid Models ◽  
Cad Cam ◽  
Implicit Modeling ◽  
Manufacturing Applications ◽  
Determine Surface Area ◽  
Implicit Solid ◽  
Aided Design

Abstract Computer-aided design/manufacturing (CAD/CAM) systems intended to support automated design and manufacturing applications such as shape generation and solid free-form fabrication (SFF) must provide not only methods for creating and editing models of objects to be manufactured, but also methods for interrogating the models. Interrogation refers to any process that derives information from the model. Typical interrogation tasks include determine surface area, volume or inertial properties, computing surface points and normals for rendering, and computing slice descriptions for SFF. While currently available commercial modeling systems generally employ a boundary representation (B-rep) implementation of solid modeling, research efforts have considered implicit modeling schemes as a potential source of improved robustness. Implicit implementations are available for a broad range of modeling operations, but interrogation operations have been widely considered too costly for many applications. This paper describes a method based on interval analysis for interrogating implicit solid models that aims at achieving both robustness and efficiency.

Algorithmen-basierte Freiformflächenstrukturierung/Generation of NC programs for the micromilling structuring of free-form surfaces – Algorithm-based free-form surface structuring

2021 ◽  
Vol 111 (11-12) ◽  
pp. 797-802
Author(s):  
Leonhard Alexander Meijer ◽  
Torben Merhofe ◽  
Timo Platt ◽  
Dirk Biermann
Keyword(s):  
Computer Aided Design ◽  
Computational Effort ◽  
Free Form ◽  
Process Chain ◽  
Surface Structuring ◽  
Computer Aided ◽  
Cad Cam ◽  
Free Form Surface ◽  
Aided Design ◽  
Free Form Surfaces

In diesem Beitrag wird ein neuer Ansatz zum Erstellen von Maschinenprogrammen zur mikrofrästechnischen Oberflächenstrukturierung vorgestellt und die Anwendung der Prozesskette für ein komplexes, industrielles Verzahnungswerkzeug beschrieben. Durch die Reduzierung des Berechnungsaufwandes in der CAD/CAM (Computer-aided Design & Manufacturing)-Umgebung können die Limitierungen konventioneller Softwarelösungen umgangen und Bearbeitungsprogramme für komplexe Strukturierungsaufgaben effizient erstellt werden.   A new method for generating machine programs for micromilling surface structuring is presented, and the application of the process chain to a complex, industrial gearing die is described. By reducing the computational effort in the CAD/CAM (Computer-aided Design & Manufacturing) environment, the problems of conventional software solutions can be avoided and complex machining programs can be created.

The CAD/CAM Interface: A 25-Year Retrospective

2005 ◽  
Vol 5 (3) ◽  
pp. 188-197 ◽  
Author(s):  
J. Corney ◽  
C. Hayes ◽  
V. Sundararajan ◽  
P. Wright
Keyword(s):  
Computer Aided Design ◽  
Future Research ◽  
Manufacturing Processes ◽  
Sheet Metal Parts ◽  
Multiaxis Machining ◽  
Computer Aided ◽  
Cad Cam ◽  
Feature Based ◽  
Manufacturing Applications ◽  
Aided Design

The vision of fully automated manufacturing processes was conceived when computers were first used to control industrial equipment. But realizing this goal has not been easy; the difficulties of generating manufacturing information directly from computer aided design (CAD) data continued to challenge researchers for over 25 years. Although the extraction of coordinate geometry has always been straightforward, identifying the semantic structures (i.e., features) needed for reasoning about a component’s function and manufacturability has proved much more difficult. Consequently the programming of computer controlled manufacturing processes such as milling, cutting, turning and even the various lamination systems (e.g., SLA, SLS) has remained largely computer aided rather than entirely automated. This paper summarizes generic difficulties inherent in the development of feature based CAD/CAM (computer aided manufacturing) interfaces and presents two alternative perspectives on developments in manufacturing integration research that have occurred over the last 25 years. The first perspective presents developments in terms of technology drivers including progress in computational algorithms, enhanced design environments and faster computers. The second perspective describes challenges that arise in specific manufacturing applications including multiaxis machining, laminates, and sheet metal parts. The paper concludes by identifying possible directions for future research in this area.

scholarly journals Direct Printed Metal Devices - The Next Level of Computer-aided Design and Computer-aided Manufacturing Applications in the Orthodontic Care

2017 ◽  
Vol 7 ◽  
pp. 253-259 ◽  
Author(s):  
Simon Graf
Keyword(s):  
Computer Aided Design ◽  
Physical Models ◽  
Orthodontic Appliances ◽  
Know How ◽  
Metal Printing ◽  
Computer Aided ◽  
Cad Cam ◽  
3D Metal Printing ◽  
Manufacturing Applications ◽  
Aided Design

As the whole world gets more digital, so do we. This article provides a basic know-how for the CAD/CAM-workflow for metallic orthodontic appliances. Demonstrating step-by-step how to design the appliance on a digital cast and laser-melting (3D metal printing) it, till the final result, without any physical models.

Morphological Offset Computing for Contour Pocketing

2006 ◽  
Vol 129 (2) ◽  
pp. 400-406 ◽  
Author(s):  
R. Molina-Carmona ◽  
A. Jimeno ◽  
R. Rizo-Aldeguer
Keyword(s):  
Computer Aided Design ◽  
Tool Path ◽  
Free Form ◽  
Computer Aided Manufacturing ◽  
Theoretical Formulation ◽  
Topological System ◽  
Computer Aided ◽  
Cad Cam ◽  
Tool Shape ◽  
Aided Design

Background. Tool path generation problem is one of the most complexes in computer aided manufacturing. Although some efficient algorithms have been developed to solve it, their technological dependency makes them efficient in only a limited number of cases. Method of Approach. Our aim is to propose a model that will set apart the geometrical issues involved in the manufacturing process from the purely technology-dependent physical issues by means of a topological system. This system applies methods and concepts used in mathematical morphology paradigms. Thus, we will obtain a geometrical abstraction which will not only provide solutions to typically complex problems but also the possibility of applying these solutions to any machining environment regardless of the technology. Presented in the paper is a method for offsetting any kind of curve. Specifically, we use parametric cubic curves, which is one of the most general and popular models in computer aided design (CAD)/computer aided manufacturing (CAM) applications. Results. The resulting method avoids any constraint in object or tool shape and obtains valid and optimal trajectories, with a low temporal cost of O(n∙m), which is corroborated by the experiments. It also avoids some precision errors that are present in the most popular commercial CAD/CAM libraries. Conclusions. The use of morphology as the base of the formulation avoids self-intersections and discontinuities and allows the system to machine free-form shapes using any tool without constraints. Most numerical and geometrical problems are also avoided. Obtaining a practical algorithm from the theoretical formulation is straightforward. The resulting procedure is simple and efficient.

Sketch-based shape exploration using multiscale free-form surface editing

2012 ◽  
Vol 26 (3) ◽  
pp. 337-350
Author(s):  
Günay Orbay ◽  
Mehmet Ersın Yümer ◽  
Levent Burak Kara
Keyword(s):  
Computer Aided Design ◽  
Free Form ◽  
Levels Of Detail ◽  
Solid Models ◽  
Free Form Surface ◽  
Conceptual Flexibility ◽  
Aided Design ◽  
Free Form Surfaces ◽  
Surface Editing ◽  
Different Levels

AbstractThe hierarchical construction of solid models with current computer-aided design systems provide little support in creating and editing free-form surfaces commonly encountered in industrial design. In this work, we propose a new design exploration method that enables sketch-based editing of free-form surface geometries where specific modifications can be applied at different levels of detail. This multilevel detail approach allows the designer to work from existing models and make alterations at coarse and fine representations of the geometry, thereby providing increased conceptual flexibility during modeling. At the heart of our approach lies a multiscale representation of the geometry obtained through a spectral analysis on the discrete free-form surface. This representation is accompanied by a sketch-based surface editing algorithm that enables edits to be made at different levels. The seamless transfer of modifications across different levels of detail facilitates a fluid exploration of the geometry by eliminating the need for a manual specification of the shape hierarchy. We demonstrate our method with several design examples.

Sustained CAD/CAE Application Integration: Supporting Simplified Models

2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Robert Kirkwood ◽  
James A. Sherwood
Keyword(s):  
Computer Aided Design ◽  
Ad Hoc ◽  
Product Development Process ◽  
Solid Models ◽  
Computer Aided ◽  
Major Subset ◽  
Cad Cam ◽  
Cad Models ◽  
Manual Interaction ◽  
Aided Design

Abstract Computer-aided design/computer-aided manufacturing/computer-aided engineering (CAD/CAM/CAE) integration offers designers, analysts, and manufacturers the opportunity to share the data throughout the product development process. Finite element (FE) meshing applications integrated with the solid model data from CAD systems represent a major subset of CAD/CAM/CAE integration. In an earlier paper, it was demonstrated that virtual persistent identifiers (VPIs) can be used to assure or repair sustained integration with successive versions of neutral-format solid models. From that article, several follow-on issues become apparent. The geometry as per the CAE model often differs from the CAD model, so even with cross-format issues resolved, significant obstacles to sustained CAD/CAE integration remain. Along with simplification, the current article investigates additional techniques for further automating the recognition of changes between CAD models, reducing the manual interaction to just a few minutes. The article goes on to demonstrate how associativity can be sustained when using current versions of neutral formats like STEP and IGES. The overall point of the paper is to show that given a precise recognition of the differences between two solid models, a generalized means of ad-hoc integration is possible. This point is demonstrated through two case studies where simplifications of the CAD geometry are made to facilitate the meshing of the part. The integration is shown to be maintained across successive versions and to address a range of simplification processing. A summary of best practices for efficiently accommodating sustained CAD/CAE integration is also presented.

scholarly journals Orthodontic digital workflow: devices and clinical applications

2021 ◽  
Vol 26 (6) ◽  
Author(s):  
Taís de Morais Alves da CUNHA ◽  
Inessa da Silva BARBOSA ◽  
Karolinne Kaila PALMA
Keyword(s):  
Digital Technology ◽  
Computer Aided Design ◽  
Treatment Time ◽  
Clinical Applications ◽  
Digital Workflow ◽  
Fixed Appliance ◽  
Computer Aided ◽  
Cad Cam ◽  
Manufacturing Applications ◽  
Aided Design

ABSTRACT Introduction: The digital technology has contributed to improve and simplify diagnosis, treatment planning and execution in Orthodontics. Among CAD/CAM system (Computer-Aided Design / Computer-Aided Manufacturing) applications in Orthodontics, we highlight the installation and removal of fixed appliance, clear aligners, customized appliances, and retainers fabricated in digital environment. This approach has several advantages for practitioner and patient, as it enhances appliances precision, directly interferes in treatment time and predictability. Even with all the benefits arising from the digital workflow, few orthodontists have adopted this technique in their clinical practice, most due to high cost and lack of technical preparation for proper execution. Objectives: Thus, given the importance of digital technology to improve specialty performance and the still incipient incorporation of digital flow in Orthodontics, the purpose of this article is to describe the available resources and clinical applications of the CAD/CAM technology in Orthodontics.

Visual assessment of free-form surfaces in CAD/CAM

1998 ◽  
Vol 212 (3) ◽  
pp. 207-214 ◽  
Author(s):  
R J Cripps ◽  
A A Ball
Keyword(s):  
Computer Aided Design ◽  
Mathematical Theory ◽  
Visual Assessment ◽  
Free Form ◽  
Design Engineers ◽  
Surface Models ◽  
Cad Cam ◽  
Aided Design ◽  
Free Form Surfaces

This paper reviews the current graphical tools available for checking the quality of CAD/CAM (computer aided design/manufacture) surface models and highlights the difficulties of their use. A new range of geometrically based tools is proposed, especially designed for the task of enabling design engineers to visually assess the quality of free-form surfaces at a workstation screen to within an accuracy comparable with working to full-scale drawings. The tools should be easy to use without recourse to understanding the underlying mathematical theory of surface differential geometry on which the techniques are ultimately based.

Real-Time Machinability Analysis of Free Form Surfaces on the GPU

2009 ◽  
Vol 9 (2) ◽  
Author(s):  
Mikola Lysenko ◽  
Roshan D’Souza ◽  
Keyvan Rahmani
Keyword(s):  
Real Time ◽  
Computer Aided Design ◽  
Graphics Processing Units ◽  
Three Dimensional ◽  
Free Form ◽  
Complex Objects ◽  
Cad System ◽  
Solid Models ◽  
Aided Design ◽  
Free Form Surfaces

In this paper a new hardware accelerated method is presented to evaluate the machinability of free-form surfaces. This method works on tessellated models that are commonly used by computer aided design (CAD) systems to render three-dimensional shaded images of solid models. Modern graphics processing units (GPUs) can be programed in hardware to accelerate specialized rendering techniques. In this research, we have developed new algorithms that utilize the programmability of GPUs to evaluate the machinability of free-form surfaces. The method runs in real-time on fairly inexpensive hardware (<$600), and performs well regardless of the surface type. The complexity of the method is dictated by the size of the projected view of the model. The proposed method can be used as a plug-in in a CAD system to evaluate the manufacturability of a part at early design stages. The efficiency and the speed of the proposed method are demonstrated on some complex objects.

Structural Analysis of Product and Computer-Aided Assembly Planning in AssemBL Software Package

2018 ◽  
pp. 11-33
Author(s):  
A. N. Bozhko
Keyword(s):  
Computer Aided Design ◽  
State Of The Art ◽  
Graph Model ◽  
Design System ◽  
Assembly Planning ◽  
Complex Products ◽  
Assembly Sequences ◽  
Computer Aided ◽  
Cad Cam ◽  
Aided Design

Computer-aided design of assembly processes (Computer aided assembly planning, CAAP) of complex products is an important and urgent problem of state-of-the-art information technologies. Intensive research on CAAP has been underway since the 1980s. Meanwhile, specialized design systems were created to provide synthesis of assembly plans and product decompositions into assembly units. Such systems as ASPE, RAPID, XAP / 1, FLAPS, Archimedes, PRELEIDES, HAP, etc. can be given, as an example. These experimental developments did not get widespread use in industry, since they are based on the models of products with limited adequacy and require an expert’s active involvement in preparing initial information. The design tools for the state-of-the-art full-featured CAD/CAM systems (Siemens NX, Dassault CATIA and PTC Creo Elements / Pro), which are designed to provide CAAP, mainly take into account the geometric constraints that the design imposes on design solutions. These systems often synthesize technologically incorrect assembly sequences in which known technological heuristics are violated, for example orderliness in accuracy, consistency with the system of dimension chains, etc.An AssemBL software application package has been developed for a structured analysis of products and a synthesis of assembly plans and decompositions. The AssemBL uses a hyper-graph model of a product that correctly describes coherent and sequential assembly operations and processes. In terms of the hyper-graph model, an assembly operation is described as shrinkage of edge, an assembly plan is a sequence of shrinkages that converts a hyper-graph into the point, and a decomposition of product into assembly units is a hyper-graph partition into sub-graphs.The AssemBL solves the problem of minimizing the number of direct checks for geometric solvability when assembling complex products. This task is posed as a plus-sum two-person game of bicoloured brushing of an ordered set. In the paradigm of this model, the brushing operation is to check a certain structured fragment for solvability by collision detection methods. A rational brushing strategy minimizes the number of such checks.The package is integrated into the Siemens NX 10.0 computer-aided design system. This solution allowed us to combine specialized AssemBL tools with a developed toolkit of one of the most powerful and popular integrated CAD/CAM /CAE systems.

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