3D Shape Engineering and Design Parameterization

Abstract

This paper presents a brief review and technical advancement on 3D shape engineering and design parameterization in reverse engineering, in which discrete point clouds are converted into feature-based parametric solid models. Numerous efforts have been devoted to developing technology that automatically creates NURBS surface models from point clouds. Only very recently, the development was extended to support parametric solid modeling that allows significant expansion on the scope of engineering assignments. In this paper, underlying technology that enables such advancement in 3D shape engineering and design parameterization is presented. Software that offers such capabilities is evaluated using practical examples. Observations are presented to conclude this study. Fig. 10: A parametric solid model of the block example created using Rapidform, (a) fully parameterized section sketch, (b) extrusion for the base block, and (c) design change.5.2.2 Method 2: Wizard Wizard, or Modeling Wizard, of Rapidform automatically extracts Wizard features such as extrude, revolve, pipe, and loft, etc., to create solid models from segmented regions. Note that a Wizard feature (terminology employed in Rapidform) can be a surface (such as pipe) or a solid feature. There are five Wizard features provided: extrusion, revolution for extracting solid features; and sweep, loft, and pipe for surface features. There are three general steps to extract features using Wizard, (1) select mesh segments to generate individual features using Wizard, (2) modify the dimensions or add constraints to the sketches extracted in order to parameterize the sketches, and (3) use Boolean operations to union, subtract, or intersect individual features for a final model if needed. A tubing example shown in Fig. 11. is employed to illustrate the capabilities offered in Wizard. We start with a polygon mesh that has been segmented, as shown in Fig. 11(a). First, we select the exterior region of the main branch and choose Pipe Wizard. Rapidform uses a best fit pipe surface to fit the main branch automatically, as shown in Fig. 11(b). Note that the Pipe Wizard generates section profile and guide curve as spatial (non-planar) spline curves, which cannot be parameterized. Also, wall thickness has to be added to the pipe to complete the solid feature. Next, we choose Revolution Wizard to create revolved features for the top and bottom flanges, as shown in Fig. 11(c). Note that each individual features are extracted separately. They are not associated. Boolean operations must be applied to these decoupled features for a final solid model.

Research and Practice on Surface Reconstruction by Region

“…The surface feature can be obtained by surface fitting. Finally, we can get the original model by Boolean operation of surfaces and models [5].…”

An evolutionary approach to the extraction of object construction trees from 3D point clouds

“…To support a higher level of interaction with reconstructed objects, obtained models have to be parameterized such that the user could modify individual parts and the entire logic of the object construction including its topology. Such a parameterized model reconstruction is required in mechanical engineering, bio-engineering, computer animation and other application areas [13].…”

“…It consists in grouping the fitted primitives to generate a valid boundary representation model [3]. Parametrized models reflecting semantics and logic of their construction are most suitable for further operating on them [13]. Feature-based parametric solid models include information on semantically meaningful parts (geometric features) with their parameters and a history tree (or a feature tree) representing the sequence of operations for constructing the model.…”

New Product Development (NPD) Process – An Example of Industrial Sector

“…In the fifties of the last century, during the development of mass production based on the Fordist model, these stages were considered sequential. The sequentially executed product development process often results in a prolonged lead-time and an elevated product cost [3]. To improve the effectiveness and efficiency of the new product development process, the sequential approach has evolved into a more integrated and simultaneous one, where the different stages are not separated and the first product concept can be modified and improved through meetings, discussions with clients and suppliers and feedbacks in every stage of the process.…”