A three-dimensional algorithm using two-dimensional slice data for building multiple parts in layered manufacturing

2000 ◽  
Vol 214 (5) ◽  
pp. 365-378 ◽  
Author(s):  
J Hur ◽  
K Lee ◽  
J Ahn ◽  
H C Lee
Keyword(s):  
Rapid Prototyping ◽  
Three Dimensional ◽  
Packing Problem ◽  
Optimal Placement ◽  
Normal Vector ◽  
Two Dimensional ◽  
Stl File ◽  
Work Volume ◽  
Time Required ◽  
Efficient Packing

In a rapid prototyping process, the time required to build multiple prototype parts can be reduced by building several parts simultaneously in a work volume. Interactive arrangement of the multiple parts, called three-dimensional nesting, is a tedious process and does not guarantee the optimal placement of all the parts. The three-dimensional nesting is well known as a problem requiring intense computation. Thus, an efficient algorithm to solve this problem is still under investigation. This paper presumes that the three-dimensional packing problem can be simplified into a set of two-dimensional irregular polygon nesting problems for each layer to take advantage of the characteristic of a rapid prototyping process, i. e. the process eventually uses two-dimensional slicing data of the STL file. The proposed algorithm uses a no-fit polygon (NFP) to calculate the allowable locations of each slice of a part such that it does not overlap other existing slices in the same z level. Then the allowable position of the part with respect to other parts already located in a work volume can be determined by obtaining the union of all NFPs that are obtained from each slice of the part. Additionally, a genetic algorithm is used to try and determine the various orders of the placement of the part and the various orientations of each part for efficient packing. Various orientations of a part are examined by rotating it about the normal vector of the slice in finite angles and by inversion. The proposed algorithm can be applied to a rapid prototyping process that does not use support structures.

AN EFFICIENT APPROACH FOR THE THREE-DIMENSIONAL CONTAINER PACKING PROBLEM WITH PRACTICAL CONSTRAINTS

2004 ◽  
Vol 21 (03) ◽  
pp. 279-295 ◽  
Author(s):  
ZHIHONG JIN ◽  
KATSUHISA OHNO ◽  
JIALI DU
Keyword(s):  
Three Dimensional ◽  
Real Life ◽  
Packing Problem ◽  
Utilization Rate ◽  
Benchmark Problems ◽  
Rectangular Container ◽  
Efficient Packing ◽  
High Degree ◽  
Practical Constraints ◽  
Inherent Stability

This paper deals with the three-dimensional container packing problem (3DCPP), which is to pack a number of items orthogonally onto a rectangular container so that the utilization rate of the container space or the total value of loaded items is maximized. Besides the above objectives, some other practical constraints, such as loading stability, the rotation of items around the height axis, and the fixed loading (unloading) orders, must be considered for the real-life 3DCPP. In this paper, a sub-volume based simulated annealing meta-heuristic algorithm is proposed, which aims at generating flexible and efficient packing patterns and providing a high degree of inherent stability at the same time. Computational experiments on benchmark problems show its efficiency.

A Simulated Annealing-Based Approach to Three Dimensional Component Packing

1994 ◽  
Author(s):  
Simon Szykman ◽  
Jonathan Cagan
Keyword(s):  
Simulated Annealing ◽  
Three Dimensional ◽  
Packing Problem ◽  
Computational Approach ◽  
Vlsi Circuits ◽  
Two Dimensional ◽  
Optimal Solutions ◽  
Layout Problem ◽  
Component Layout ◽  
General Component

Abstract This paper introduces a computational approach to three dimensional component layout that employs simulated annealing to generate optimal solutions. Simulated annealing has been used extensively for two dimensional layout of VLSI circuits; this research extends techniques developed for two dimensional layout optimization to three dimensional problems which are more representative of mechanical engineering applications. In many of these applications, miniaturization trends increase the need to achieve higher packing density and fit components into smaller containers. This research addresses the three dimensional packing problem, which is a subset of the general component layout problem, as a framework in which to solve general layout problems.

A Review on Fabricating Procedures in Rapid Prototyping

2016 ◽  
Vol 6 (2) ◽  
pp. 23-40 ◽  
Author(s):  
Ganzi Suresh ◽  
K. L. Narayana
Keyword(s):  
Rapid Prototyping ◽  
Computer Aided Design ◽  
Three Dimensional ◽  
Rapid Manufacturing ◽  
Two Dimensional ◽  
Computer Aided ◽  
Aided Design ◽  
Crude Material

Rapid prototyping (RP) advancements are in light of the rule of making three-dimensional geometries straightforwardly from computer aided design (CAD) by stacking two-dimensional profiles on top of one another. Rapid manufacturing (RM) is the utilization of rapid prototyping advancements to make end-utilize or completed items. Aside from the ordinary assembling methods which are utilized for quite a while assembling of an item, added substance assembling methodologies have picked up force in the late years. The explanation for this is that these techniques don't oblige extraordinary tooling and don't evacuate material which is exceptionally advantageous really taking shape of a segment. Rapid manufacturing is the developing innovation in assembling commercial ventures with a specific end goal to create the model inside the less time and expense effective. In this paper we talked about a portion of the fast assembling advancements in light of the sort of crude material is utilized for the procedures, applications, preferences and limits.

THE TWO-DIMENSIONAL PACKING PROBLEM FOR IRREGULAR OBJECTS

2004 ◽  
Vol 13 (03) ◽  
pp. 429-448 ◽  
Author(s):  
PING CHEN ◽  
ZHAOHUI FU ◽  
ANDREW LIM ◽  
BRIAN RODRIGUES
Keyword(s):  
Genetic Algorithms ◽  
Basic Problem ◽  
Piecewise Linear ◽  
Three Dimensional ◽  
Packing Problem ◽  
Two Dimensional ◽  
Linear Representations ◽  
Rectangular Packing ◽  
Work Done ◽  
Cutting Problems

Packing and cutting problems arise in a wide variety of industrial situations. The basic problem is that of determining a good arrangement of objects in a region without any overlap. Much research has been done on two and three dimensional rectangular packing while there has been little work done on irregular packing. In this work, we study the two-dimensional irregular packing problem and provide heuristic solutions which use rectilinear and piecewise-linear representations of objects. These heuristics include Genetic Algorithms and Tabu Search. Experimentation gives good results.

Reducing two-dimensional rearfoot motion variability during walking

1993 ◽  
Vol 83 (7) ◽  
pp. 394-397 ◽  
Author(s):  
MW Cornwall ◽  
TG McPoil
Keyword(s):  
Dimensional Analysis ◽  
Clinical Setting ◽  
Three Dimensional ◽  
Movement Analysis ◽  
Two Dimensional ◽  
Motion Measurements ◽  
Time Required ◽  
Rearfoot Motion

Although three-dimensional movement analysis is the preferred method of assessing rearfoot motion during gait, the high cost of equipment and the time required to use it often make it unreasonable or impractical in a clinical setting. The authors discuss a method of minimizing the variability of rearfoot motion measurements during walking, using two-dimensional analysis when three-dimensional is not available to the clinician.

A Review on Fabricating Procedures in Rapid Prototyping

3D Printing ◽  
2017 ◽  
pp. 1-21 ◽  
Author(s):  
Ganzi Suresh ◽  
K. L. Narayana
Keyword(s):  
Rapid Prototyping ◽  
Computer Aided Design ◽  
Three Dimensional ◽  
Rapid Manufacturing ◽  
Two Dimensional ◽  
Computer Aided ◽  
Aided Design ◽  
Crude Material

Rapid prototyping (RP) advancements are in light of the rule of making three-dimensional geometries straightforwardly from computer aided design (CAD) by stacking two-dimensional profiles on top of one another. Rapid manufacturing (RM) is the utilization of rapid prototyping advancements to make end-utilize or completed items. Aside from the ordinary assembling methods which are utilized for quite a while assembling of an item, added substance assembling methodologies have picked up force in the late years. The explanation for this is that these techniques don't oblige extraordinary tooling and don't evacuate material which is exceptionally advantageous really taking shape of a segment. Rapid manufacturing is the developing innovation in assembling commercial ventures with a specific end goal to create the model inside the less time and expense effective. In this paper we talked about a portion of the fast assembling advancements in light of the sort of crude material is utilized for the procedures, applications, preferences and limits.

Comparison between Two-Dimensional and Three-Dimensional Assessments of the Fetal Corpus Callosum: Reproducibility of Measurements and Acquisition Time

2021 ◽  
Author(s):  
Jonathan Baert ◽  
Léo Pomar ◽  
Ali Mchirgui ◽  
Véronique Lambert ◽  
Gabriel Carles ◽  
...  
Keyword(s):  
Quality Control ◽  
Linear Regression ◽  
Corpus Callosum ◽  
Three Dimensional ◽  
Correlation Coefficients ◽  
Acquisition Time ◽  
Two Dimensional ◽  
3D Measurements ◽  
Time Required ◽  
2D And 3D

AbstractThe objective is to study the reproducibility and reliability of the fetal corpus callosum measurements between two-dimensional (2D) and three-dimensional (3D) acquisitions. This prospective study enrolled 475 fetuses, monitored between 18 and 38 weeks of gestation by two operators. Starting from a transcerebellar axial plane, 3D and 2D mid-sagittal views of the corpus callosum were obtained. Measurements of length and thickness were performed and underwent quality control by independent reviewers. The acquisition time of the two methods was measured. Means, differences, and linear correlations were analyzed using t-test, regression and Pearson's correlation coefficients, and Bland–Altman's plots. This analysis was performed for each operator to test the interobserver reproducibility. Among the 432 cases measured using both methods, 380 (88%) were validated by quality control. The mean corpus callosum length and thickness were essentially the same using 2D and 3D measurements (2D: 33.8 ± 8.7 vs. 3D: 33.7 ± 8.7 mm, 2D: 2.2 ± 0.4 vs. 3D: 2.2 ± 0.4 mm, respectively; mean ± standard deviation [SD]). Linear regression coefficients and Pearson's coefficients were similar for length (2D: 0.8283 and 0.9191 vs. 3D: 0.8271 and 0.9095), but slightly different regarding thickness (2D: 0.6775 and 0.8231 vs. 3D: 0.5831 and 0.7636). Differences between 2D and 3D measurements, considering Bland–Altman's plots and correlated with gestational age, were acceptable (2D: 0.097 ± 0.559 mm, 3D: 0.004 ± 0.111 mm). The acquisition time required was significantly lower for 3D acquisitions (3D: 25.2 ± 14.5 seconds vs. 2D: 35.1 ± 19.4 seconds, p < 0.01). Linear regression and Pearson's coefficients for the measurements of corpus callosum length and thickness using 2D or 3D acquisitions did not differ between the operators. This study confirms good reproducibility of corpus callosum assessment by transabdominal 3D acquisitions. The good feasibility in routine scans may lead to better screening for callosal dysgenesis.

scholarly journals Computer simulation and system realization of jacquard weft-knitted fabric

2019 ◽  
Vol 14 ◽  
pp. 155892501989526
Author(s):  
Lanming Jin ◽  
Qiao Xu
Keyword(s):  
Computer Simulation ◽  
Spatial Data ◽  
Three Dimensional ◽  
Knitted Fabric ◽  
Two Dimensional ◽  
Three Dimensional Model ◽  
Weft Knitted Fabric ◽  
Virtual Fabric ◽  
Time Required ◽  
Prediction And Simulation

Jacquard weft-knitted fabric is a type of multilayer knitting fabric which has a stereoscopic surface with complex patterns. A computer simulation system was established, based on a virtual fabric Unity3D platform, to minimize the time required for computer simulation and to enhance the simulation results. The three-dimensional fabric data were unified and coordinate data were obtained to achieve the establishment. Three factors of simulation algorithm for jacquard weft-knitted fabric were used to establish and control the effect of a fabric model. By integrating three-dimensional model data, two-dimensional spatial data, and gray model, virtual simulation based on three-dimensional engine Unity3D platform was realized. Based on the real-fabric data, the final fabric patterns were predicted from macroscopic angle instead of two-dimensional and microscopic simulations. The system is proved to be more effective for the prediction and simulation of jacquard weft-knitted fabric and other fabrics having similar stereoscopic surfaces.

High Resolution Microscopy of Multi-Layered Biological Crystals

1982 ◽  
Vol 40 ◽  
pp. 80-83
Author(s):  
H.A. Cohen ◽  
T.W. Jeng ◽  
W. Chiu
Keyword(s):  
High Resolution ◽  
Low Dose ◽  
Three Dimensional ◽  
Data Interpretation ◽  
Two Dimensional ◽  
Biological Objects ◽  
Density Maps ◽  
Density Map ◽  
Complex Crystal ◽  
High Resolution Microscopy

This tutorial will discuss the methodology of low dose electron diffraction and imaging of crystalline biological objects, the problems of data interpretation for two-dimensional projected density maps of glucose embedded protein crystals, the factors to be considered in combining tilt data from three-dimensional crystals, and finally, the prospects of achieving a high resolution three-dimensional density map of a biological crystal. This methodology will be illustrated using two proteins under investigation in our laboratory, the T4 DNA helix destabilizing protein gp32*I and the crotoxin complex crystal.

Instrumentation For Quantitative Microscopy

1977 ◽  
Vol 35 ◽  
pp. 206-209
Author(s):  
B. Ralph ◽  
A.R. Jones
Keyword(s):  
Volume Fraction ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Automatic Data ◽  
Phase Volume Fraction ◽  
Statistical Confidence ◽  
Resultant Data ◽  
Automatic Data Collection ◽  
Third Dimension ◽  
Evolution Of Microstructure

In all fields of microscopy there is an increasing interest in the quantification of microstructure. This interest may stem from a desire to establish quality control parameters or may have a more fundamental requirement involving the derivation of parameters which partially or completely define the three dimensional nature of the microstructure. This latter categorey of study may arise from an interest in the evolution of microstructure or from a desire to generate detailed property/microstructure relationships. In the more fundamental studies some convolution of two-dimensional data into the third dimension (stereological analysis) will be necessary.In some cases the two-dimensional data may be acquired relatively easily without recourse to automatic data collection and further, it may prove possible to perform the data reduction and analysis relatively easily. In such cases the only recourse to machines may well be in establishing the statistical confidence of the resultant data. Such relatively straightforward studies tend to result from acquiring data on the whole assemblage of features making up the microstructure. In this field data mode, when parameters such as phase volume fraction, mean size etc. are sought, the main case for resorting to automation is in order to perform repetitive analyses since each analysis is relatively easily performed.

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