Similarity of Tessellated Solid Models for Engineering Applications

Author(s):  
Rahul S. Renu ◽  
Christopher Sousa

The objective of this research is to investigate the performance of a solid model similarity assessment method. This method is used to assess the similarity of tessellated solid models, where the tessellated geometry is in the form of triangles — specifically, the method compares STL files. A histogram of (triangle) tessellation areas is generated for each solid model being compared. The difference in the histograms of two solid models indicates their dissimilarity. The performance of the solid model similarity assessment method is evaluated by varying tessellation resolutions, and by varying histogram bin sizes. The solid model similarity assessment method is also compared to methods from literature. The comprehensive testing was performed using 867 solid models from the Engineering Shape Benchmark. It is found that the method was robust in its sensitivity to histogram bin sizes, and robust in its sensitivity to tessellation resolution. It is found that for small retrieval sizes, precision is relatively high. It is also found that this method outperformed methods from literature when comparing models that are rectangular, flat, thin, and/or cubic. Additionally, shortcomings of this method and related future work is identified.

2012 ◽  
Vol 215-216 ◽  
pp. 270-274 ◽  
Author(s):  
Song Qiao Tao ◽  
Wei He

3D CAD model retrieval has received a lot of attentions in the academic community. Most existent methods for 3D model similarity assessment focus on component models instead of assembly models. In this paper, an assembly model similarity assessment method is presented in order to find the similar assemblies model for design reuse. First, assembly model is described as component attributed relational graph. Then, the compatibility matrix between two assemblies is calculated, which serves as the measure of their similarity. Finally, the optimal matching under the measures is calculated using Hungarian Method. Experimental results show that this method is able to support the assembly similarity evaluation.


2012 ◽  
Vol 2012 ◽  
pp. 1-20 ◽  
Author(s):  
Alvaro Valencia ◽  
Benjamin Blas ◽  
Jaime H. Ortega

This study investigates the effects of different solid models on predictions of brain shift for three craniotomies. We created a generic 3D brain model based on healthy human brain and modeled the brain parenchyma as single continuum and constrained by a practically rigid skull. We have used elastic model, hyperelastic 1st, 2nd, and 3rd Ogden models, and hyperelastic Mooney-Rivlin with 2- and 5-parameter models. A pressure on the brain surface at craniotomy region was applied to load the model. The models were solved with the finite elements package ANSYS. The predictions on stress and displacements were compared for three different craniotomies. The difference between the predictions of elastic solid model and a hyperelastic Ogden solid model of maximum brain displacement and maximum effective stress is relevant.


2021 ◽  
Author(s):  
Rahul Sharan Renu ◽  
Gregory Mocko

Abstract Many manufacturing enterprises have large collections of solid models and text-based assembly processes to support assembly operations. These data are often distributed across their extended enterprise. As these enterprises expand globally, there is often an increase in product and process variability which can often lead to challenges with training, quality control, and obstacles with change management to name a few. Thus, there is a desire to increase the consistency of assembly work instructions within and across assembly locations. The objective of this research is to retrieve existing 3d models of components and assemblies and their associated assembly work instructions. This is accomplished using 3d solid model similarity and text mining of assembly work instructions. Initially, a design study was conducted in which participants authored assembly work instructions for several different solid model assemblies. Next, a geometric similarity algorithm was used to compute similarity scores between solid models and latent semantic analysis is used to compute the similarity between text-based assembly work instructions. Finally, a correlation study between solid model-assembly instruction tuples is computed. A moderately strong positive correlation was found to exist between solid model similarity scores and their associated assembly instruction similarity scores. This indicates that designs with a similar shape have a similar assembly process and thus can serve as the basis for authoring new assembly processes. This aids in resolving differences in existing processes by linking three-dimensional solid models and their associated assembly work instructions.


1989 ◽  
Vol 160 ◽  
Author(s):  
Dimitri D. Vvedensky ◽  
Shaun Clarke

AbstractThe epitaxial growth kinetics of Co on Cu(100) are investigated with a kinetic solid-on-solid model. Two effects are found to dominate the growth of this system reflecting the difference in surface free energies betweenthe two materials: the difference of diffusion parameters, and the inability of Co to wet Cu(100) at lower temperatures.


Author(s):  
Carol Hubbard ◽  
Yong Se Kim

Abstract As the extensive use of solid models becomes widespread, it is important to have a mechanism by which existing engineering drawings can be converted into solid models. Therefore, a geometric assistant which can aid in the construction of solid models is beneficial. In this paper, we present key operations for a system called the Assistant for the Rapid Construction of Solids (ARCS), that provides this assistance given a set of two orthographic views. ARCS is based on the Visual Reasoning Tutor (VRT), a system we developed that provides users with the geometric framework to build polyhedral solids from their orthographic views. However, the geometric domain of ARCS encompasses non-polyhedral solids with cylindrical and spherical surfaces, such as those found in typical mechanical parts. We have devised the Cylindrical and Spherical Warping operations to create cylindrical and spherical surfaces, which use interactive computer graphics that guide a human user to build non-polyhedral faces of a solid. These operations are then illustrated with an example using ARCS to create the solid model of a typical mechanical part from its orthographic projections.


2021 ◽  
Vol 28 (6) ◽  
pp. 1-12
Author(s):  
Audrey Desjardins ◽  
Oscar Tomico ◽  
Andrés Lucero ◽  
Marta E. Cecchinato ◽  
Carman Neustaedter

In this introduction to the special issue on First-Person Methods in (Human-Computer Interaction) HCI, we present a brief overview of first-person methods, their origin, and their use in Human-Computer Interaction. We also detail the difference between first-person methods, second-person, and third-person methods, as a way to guide the reader when engaging the special issue articles. We articulate our motivation for putting together this special issue: we wanted a collection of works that would allow HCI researchers to develop further, define, and outline practices, techniques and implications of first-person methods. We trace links between the articles in this special issue and conclude with questions and directions for future work in this methodological space: working with boundaries, risk, and accountability.


1996 ◽  
Vol 80 (2) ◽  
pp. 458-463 ◽  
Author(s):  
T. Reybrouck ◽  
L. Mertens ◽  
N. Kalis ◽  
M. Weymans ◽  
M. Dumoulin ◽  
...  

In pediatric exercise testing, conventional measures of aerobic exercise function such as maximal O2 uptake or the ventilatory anaerobic threshold (VAT) use only one value for the assessment of exercise capacity. We studied a more comprehensive approach to evaluate aerobic exercise function by analyzing the steepness of the slope of CO2 production (VCO2) vs. VO2 above the VAT (S3). This was calculated in 32 patients operated on for congenital heart disease [16 for transposition of the great arteries (TGA) and 16 for tetralogy of Fallot (TF)] and was compared with 16 age-matched controls (nl). The results show that the reproducibility of this new assessment method was excellent (coefficient of variation for S3: 8.6%). S3 was significantly steeper (P<0.05) in the patients (1.31 +/- 0.22 for TGA and 1.28 +/- 0.16 for TF) compared with the nl (1.10 +/- 0.22). Also, the difference between S3 and the slope of VCO2 vs. VO2 below the VAT was significantly higher in the patients (0.37 +/- 0.22 for TGA and 0.31 +/- 0.10 for TF) than in controls (0.22 +/- 0.06). The steeper slopes were associated with lower than normal values for VAT and O2 during exercise. It is concluded that the analysis of the steepness of the slope of CO2 is a sensitive, reproducible, and objective approach to evaluate the integrative cardiopulmonary response to exercise. It complements the assessment of a subnormal VAT by reflecting the extent of anaerobic metabolism.


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