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Building product models, terminologies, and object type libraries
Published in Pieter Pauwels, Kris McGlinn, Buildings and Semantics, 2023
Aaron Costin, Jeffrey W. Ouellette, Jakob Beetz
Product models are developed using the method of solid modelling. Solid modelling is a method of using mathematical equations to computer generate three-dimensional solids. Solid modelling is distinguished from other areas in geometric modelling and computing by its emphasis on informational completeness, physical fidelity, and universality [352]. Two main concepts for doing so include geometric modelling and parametric modelling. Geometric modelling, which is the use of solid representation schemes (e.g., constructive solid geometry (CSG), boundary representation (B-rep)), is the foundation for most product representations because geometry is essential for design, analysis, and production. Parametric modelling, on the other hand, is an advanced technique that uses parameters and dependencies to define a model. Parameters are essential for large models, such as building and bridges, because the user only needs to change the parameters instead of manually changing each dimension or definition with each change in design. The notions of object-based modelling and parametric modelling of buildings have their roots in the concepts of parametric solid modelling for generic product modelling.
Modeling and virtual prototyping
Published in Fuewen Frank Liou, Rapid Prototyping and Engineering Applications, 2019
Many types of commercial software are excellent virtual prototyping tools, and often they start with a CAD model to define the product geometry. CAD models could be a wireframe, surface model, or solid model. Solid modeling stores many details of the model and hence needs more space to store the data. However, today’s computer systems are fast and with ample memory; thus, solid modeling is being extensively used. The benefits of solid modeling include better visualization with greater detail, the ability to perform engineering analysis and computer simulation, and efficient transfer of data files between different software packages. Figure 3.43 shows an example of mold design details. Similar to this example, often a picture is worth a thousand words and expresses the concept effectively.
Methodologies of Feature Representations
Published in Awais Ahmad Khan, Emad Abouel Nasr, Abdulrahman Al-Ahmari, Syed Hammad Mian, Integrated Process & Fixture Planning, 2018
Awais Ahmad Khan, Emad Abouel Nasr, Abdulrahman Al-Ahmari, Syed Hammad Mian
Solid modeling overcomes the limitations of both wireframe and surface modeling by providing a comprehensive solid definition to a 3D object [17]. This technique represents the solid object as a volumetric description, including both the surface and edge definitions of an object. The mass, volume, and surface properties, and so on can be derived using solid models [21]. Moreover, solid modeling provides topological information in addition to the geometrical information, which helps to represent the solid unambiguously. The emergence of solid modeling systems allowed designers to develop virtual prototypes or software for visualization and analysis. There are several representation schemes developed and used in the solid modeling software such as constructive solid geometry (CSG), boundary representation (B-rep), primitive instancing, cell decomposition, and so on. The most popular representation schemes for CAD solid modeling packages are CSG and B-rep [13,15].
A new method of the top-down parametric design for quick subdivision based on constraints
Published in Journal of Marine Engineering & Technology, 2019
Conventional geometric modelling technology represents the geometric model with wireframe model, surface model, or solid model. B-rep (boundary representation) and CSG (constructive solid geometry) are the dominant methods of solid modelling in the practical engineering field (Yu et al. 2010). However, these methods suffer from following defects when being applied in ship engineering. B-rep is based on the 2D surface manifold, while CSG is based on regular solid objects. In theory, the representation of solid model is not complete.The coverage of solid modelling is limited and the boundary of the model must be manifold, which cannot meet the engineering demands of a ship.Wireframe, surface or solid is represented separately by conventional models and cannot meet the needs of different expression models in the process of ship design.
Implementation of analytical boundary simulation method for cutting force prediction model in five-axis milling
Published in Machining Science and Technology, 2018
Hendriko Hendriko, Gandjar Kiswanto, Jos Istiyanto, Emmanuel Duc
Solid modeling provides more accurate information but requires significant computation time. Meanwhile, discretization methods reduce the calculation time compared with solid modeling. However, the computation time increases as the precision and accuracy are improved. To overcome such problems, Budak et al. (2009) and Tunc and Budak (2009) proposed a simple analytical method called the bounding point coordinate method to define the cut geometry during five-axis milling. Tests showed that the proposed method could accurately predict the depth of a cut. However, this technique is only applicable to a flat workpiece surface. When the workpiece surface was a free-form surface, the researchers used a discretization method to represent the workpiece surface.
BIM/GIS integration for web GIS-based bridge management
Published in Annals of GIS, 2021
Junxiang Zhu, Yi Tan, Xiangyu Wang, Peng Wu
Generally, in the field of modelling, there are three basic methods for solid modelling, including boundary representation (Brep), constructive solid geometry (CSG) and sweeping. IFC also uses these terms and has defined IfcSolidModel, which is the common abstract supertype of Brep, CSG representation, sweeping representation and other suitable solid representation schemes. In addition, IFC takes one step further and has defined many sub-types of these methods, such as advanced swept solid. Among them, Brep and swept solid are the most common methods.