Triangular Mesh and Boundary Representation Combined Approach for 3D CAD Lightweight Representation for Collaborative Product Development

Abstract

The lightweight representation of three-dimensional computer-aided design (3D CAD) models has drawn much attention from researchers as its usefulness in collaborative product development is vast. Existing approaches are mostly based on feature depression or mesh-based simplification. In this article, a new approach for 3D CAD lightweight representation based on combining triangular mesh representation and boundary representation (B-rep) is proposed. The corresponding data structure as well as the conversion method from original data given in B-rep was developed. Considered as an essential application in collaborative product development, a case study on the visualization process of large-scale assembly models represented in the proposed lightweight representation was also conducted. The validation of the approach was performed via experiments with 3D CAD models in SAT format and by benchmarking with the conventional all-faceted approach with the same level of mesh resolution.

STEP and IFC export to X3D

“…A way to reduce this computation time is to let the CAD Kernel compute the tessellation and export the result to X3D as a mesh node among all available (IndexedFaceSet, IndexedTriangleSet, TriangleSet etc.). This solution dispenses the viewer with the computation before rendering, thus resulting in a performance gain [Nguyen, 2019]. However, it comes with a semantic loss because the mesh, regardless of the precision, can only be an approximated representation of the surface.…”

A Method to Minimize the Data Size of a Lightweight Model for Ship and Offshore Plant Structure Using Part Characteristics

“…The basic shapes such as box, cylinder, sphere, cone, and pyramid are smaller in size than representing them using triangular meshes, because not only the parameter information, but also information such as dimension and position is stored. With regard to this, Nguyen et al [18] proposed a method for reducing the size of lightweight models by representing a triangular mesh model and a B-rep model in hybrid. Furthermore, Eigner et al [19] suggested a method for using the JT file together with an XML file that contains additional information in order to improve the utilization of the JT file.…”

“…This is because the shape can be configured by combining the stored data simply with no additional complex computations for restoration. Conventional methods to store a lightweight model can be categorized into the following three categories: the method to store a 3D shape as triangular mesh [23], the method to store only parameter values needed to define primitives which are used to represent a 3D shape [12], and the method to store both triangular mesh and B-rep elements [18]. The first method requires no additional work other than creating a triangular mesh from a 3D CAD model, but the file size is large.…”

An Automated Training of Deep Learning Networks by 3D Virtual Models for Object Recognition

“…An important task is to make a bridge between the 3D design software and teaching software (CNN frame-work). The research related to 3D design can be found in various papers, e.g., about parameter enhancement in a 3D model [15], 3D CAD (Computer Aided Design) lightweight representation [16], or design process automation [17]. The automated sample generation from 3D models can be simplified using a web interface.…”