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STandard for the Exchange of Product Model Data (STEP) is a neutral format file that carries life cycle information of solid models. The main objective of the neutral file is to communicate or exchange the data with different CAD/CAM systems. There are different neutral files before the evolution of STEP file like IGES, DXF, STL etc., but these neutral files could not carry the lifecycle data of the...
Injection molding is commonly used for fabricating plastic parts of consumer products. In this method, melted hot material is highly pressurized and forced into a space between the mold core and cavity. Thin wall shapes in the mold core are often deformed in the injection process, and plastic parts with defective shapes are produced. Detection of such problems in the manufacturing process causes costly...
The study of oil droplet spreading behaviors after oblique collision with wall is a foundation work for better understanding the complex two-phase flow in an aero engine bearing chamber. Considering the limitations in the present study, a three dimension symmetrical numerical calculation model using Volume of Fluid(VOF)method and an experimental setup about oil droplet-solid surface oblique collision...
The presented simulation model of surface tension and wettability based on physical properties of liquids is designed for use in computer graphics. Due to the relatively small surface tension forces the model is useful for simulating liquid of small volume such as droplets. This model can be used in conjunction with various fluid simulation methods, one of the most popular - Marker and Cell - has...
Madeup is a programming language for making things up-literally. Programmers write sequences of commands to move and turn through space, tracing out shapes with algorithms and mathematical operations. The language is designed to teach computation from a tangible, first-person perspective and help students integrate computation back into the physical world. We describe the language in general and reflect...
3D model is normally designed by 3D-CAD software or animation software, but a 3D direct drawing method is still a developing research. In a previous study, we suggest a 3D direct drawing method for polygonal/curved surface model using Microsoft Kinect. In this study, some subjects performe the gesture expressing a solid, analyzed the gesture trajectory. And we construct the creating solid algorithm...
Pipeline health is crucial to the continuous and uninterrupted flow of oil, gas, or any liquid. Pipelines in the oil industry are critical, where any damage or loss in their integrity; imply massive environmental and economic cost. Therefore, an a priori prediction of failure is of particular interest and can be a key to safe and interrupted operation of pipelines. To accurately predict failure, some...
This paper proposes several lightweight local 3D shape features for 3D voxel data that yield compact binary feature vectors. These features are inspired by compact binary features for 2D image, namely, Local Binary Pattern (LBP) [22], BRIEF [6] and ORB [26]. In addition to being compact, extraction of proposed 3D features is inexpensive. Furthermore, these binary feature vectors are very efficient...
While the growing demand for new building models contained in virtual worlds, games, and movies, makes the easy and fast creation of modifiable models more and more important, 3D modeling of buildings can be a tedious task due to their sometimes complex geometry. For historic buildings, especially the roofs can be challenging. We present a new method of combining simple building solids to form more...
Quality and microstructure of materials are strongly affected by the shapes of pores in solids, which are encountered in almost all the packaging, micro-electro-mechanical systems (MEMS), and manufacturing fields. This study theoretically analyzes the mechanisms of an entrapped micro-bubble as a pore in the solid. A phase diagram, as introduced previously to be satisfied by interfacial normal stress...
Recently, nanocomposite materials have attracted much attention in electrical treeing. In this study, we carried out a three-dimensional (3D) tree simulation using two macrosized fillers (i.e., spherical and discoid) as the first step in considering simulated trees in nanocomposite materials. Moreover, we carried out a comparison of simulated tree shapes depending on filler type. The results indicate...
In this study, the gas-solid two-phase flow in a CFB riser was simulated by means of LES-DSMC method. The flow regime of descending clusters at the wall was characterized. The variations of their solid concentration, velocity during descending were studied. Meanwhile, the flow behaviors of particles within them were analyzed too. The results showed that clusters at the wall are dynamic collections...
This paper presents a solid blending method with up to curvature continuities. The method is based on the solution to a vector-valued sixth order partial differential equation containing three parametric variables subjected to solid blending boundary constraints. A simple and efficient method is developed to solve the partial differential equation. The shape of the created blending solids is manipulated...
Web-based online submission of computer aided design (CAD) models for prototype parts is getting popular among service bureaus and gaining wider acceptance among rapid prototyping users. In the web based rapid prototyping (RP), an instant quote needs to be generated for an arbitrary polygonal model (usually in STL format). Hence the manufacturability analysis of polygonal models is critical in automating...
The leading method for studying radiation transport and interaction continues to be the use of Monte Carlo simulations. However, it requires the geometry be provided in a unique manner, without providing robust or user-friendly tools. One often has to “manually” translate a shape of a target into the Monte Carlo codes; it is very difficult to create the actual detailed geometry. The neutron transport...
This paper develops a new trivariate hierarchical spline scheme for volumetric data representation. Unlike conventional spline formulations and techniques, our new framework is built upon a novel parametric domain called Generalized PolyCube (GPC), comprising a set of regular cubes being glued together. Compared with the conventional PolyCube (PC) that could serve as a "one-piece'' 3-manifold...
Feature-based solid modelling systems has been widely use in product design. Ideally the models generated within these solid modelling systems can be reused in downstream operations, such as finite element analysis. However, for engineering analysis an abstracted model is usually more appropriate, in term of accuracy and efficiency. This paper describes an automated approach to approximate an abstract...
This paper describes a similarity retrieval technique for textured 3D models. Various kinds of research have been conducted on similarity retrievals of 3D models since the late 1990's. Although most of the retrieval techniques focus on shape similarity of the 3D models, our technique allows users to retrieve and classify 3D models based on texture pattern similarity. To test our texture similarity...
In this paper, we propose a concept and present CRAYON, a three dimensional (3D) solid modeling system on the CAVE, to realize a user's concept to a virtual world. CRAYON adopts a set of rules for conversion of a linear drawing into a solid in order to realize what a user wants to get. Considering positions of line vertices, CRAYON determines the position and size of a solid, and displays it on the...
This paper presents an algorithm to approximate a solid model by a hierarchical set of bounding ellipsoids having optimal shape and volume approximation errors. The ellipsoid-tree is constructed in a top-down splitting framework. Starting from the root of hierarchy the volume occupied by a given model is divided into k sub-volumes where each is approximated by a volume bounding ellipsoid and will...
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