Converting Between PLY and Ballistic Research Lab-Computer-Aided Design (BRL-CAD) File Formats

2015 ◽  
Author(s):  
Rishub Jain
Keyword(s):  
Computer Aided Design ◽  
File Formats ◽  
Computer Aided ◽  
Aided Design

Reconstruction of Trimmed NURBS Surfaces for Gap-Free Intersections

2020 ◽  
Vol 20 (5) ◽  
Author(s):  
Benjamin Urick ◽  
Richard H. Crawford ◽  
Thomas J. R. Hughes ◽  
Elaine Cohen ◽  
Richard F. Riesenfeld
Keyword(s):  
Computer Aided Design ◽  
Engineering Practice ◽  
Global Parameter ◽  
Trimmed Surfaces ◽  
File Formats ◽  
Modern Engineering ◽  
Computer Aided ◽  
Step Algorithm ◽  
Aided Design ◽  
User Knowledge

Abstract The modern engineering technologies of computer-aided design (CAD), computer-aided engineering (CAE), and computer-aided manufacturing (CAM) are ubiquitous in engineering practice. They are focused on creating, analyzing, and fabricating engineering artifacts represented as geometric models. Historically, these technologies developed independently, with different geometric representations that are customized to the needs of the technology. As a result, the combined use of these technologies has led to differences in data structures, file formats, and user knowledge and practice, requiring translation of representations between systems to support interoperability. Complicating this situation is the approximate nature of modeling operations in CAD systems, which can result in gaps at the boundary curves between mating trimmed surfaces of a model. The research presented here is aimed at removing the gaps between trimmed surfaces, resulting in a “watertight” model that is suitable for use directly by downstream applications. A three-step algorithm is presented that includes analysis of the parametric space of the trimming curves, reparameterization to create a global parameter space, and reconstruction of the intersecting surfaces to ensure continuity at the trimming curve.

Questions of authenticity: challenges in archiving born-digital design records

2010 ◽  
Vol 35 (3) ◽  
pp. 23-29
Author(s):  
Kurt G. F. Helfrich
Keyword(s):  
North America ◽  
Computer Aided Design ◽  
Digital Design ◽  
File Formats ◽  
Computer Aided ◽  
Digital Objects ◽  
Design Firms ◽  
Guidelines And Standards ◽  
Aided Design

Born-digital design records are among the most interesting and challenging digital objects that archivists have to preserve. Currently transitioning from 2-D to 3-D computer-aided design imaging applications in proprietary file formats, design firms and their future archivists face real obstacles in preserving and making these materials accessible in the long term. This article examines three recent web projects/resources in Europe and North America that have attempted to establish guidelines and standards for archiving these objects, and discusses upcoming projects at the British Architectural Library’s Drawings & Archives Collections to tackle collecting born-digital design records.

Reconstruction of Gap-Free Intersections for Trimmed NURBS Surfaces

2019 ◽  
Author(s):  
Benjamin Urick ◽  
Richard H. Crawford ◽  
Thomas J. R. Hughes ◽  
Elaine Cohen ◽  
Richard F. Riesenfeld
Keyword(s):  
Computer Aided Design ◽  
Global Parameter ◽  
Trimmed Surfaces ◽  
File Formats ◽  
Modern Engineering ◽  
Combined Use ◽  
Computer Aided ◽  
Step Algorithm ◽  
Aided Design ◽  
User Knowledge

Abstract The modern engineering technologies of Computer-Aided Design (CAD), Computer-Aided Engineering (CAE) and Computer-Aided Manufacturing (CAM) are ubiquitous in engineering design. They are focused on creating, analyzing, and fabricating objects represented as geometric models. Historically, these technologies developed independently, such that their geometric representations are customized to the needs of the technology. As a result, combined use of these technologies has led to differences in data structures, file formats, software constraints, and user knowledge and practice, requiring translation of representations between systems to support interoperability. Complicating this situation is the approximate nature of modeling operations in CAD systems, which can result in gaps at the boundary curves between mating trimmed surfaces of a model. The research presented here is aimed at removing the gaps between trimmed surfaces, resulting in a “watertight” model that is suitable for use directly by downstream applications. A three-step algorithm is presented that includes analysis of the parametric space of the trimming curves, reparameterization to create a global parameter space, and reconstruction of the intersecting surfaces to ensure continuity at the trimming curve.

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