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This study presents a new method for reconstructing an adaptive underlying surface, S ~ , from scanned data for styling design objects. S ~ is usually generated by sweeping a curve that varies its shape gradually while being swept. However, when S ~ is reconstructed from a segmented part of the scanned data, it is generally more difficult to control the gradual variation as the ratio of the segmented part to the area of S ~ becomes smaller. Therefore, this study represents S ~ by the sum of two surfaces, S ~ = S U + S Δ . Here, an underlying surface S U is generated by the standard sweep method and the difference surface S Δ not only compensates for the error between S ~ and the scanned data but also exhibits monotonous change in the curvatures. Consequently, the gradual change in a curve being swept is represented by S Δ , which does not encounter the aforementioned problem because it is intended to control the deviation from the "reference" S U under the constraint of "curvature monotonicity." The experimental results demonstrate the validity of surface reconstruction from real-world scanned data as well as an application of the proposed method. [ABSTRACT FROM AUTHOR]

Tolerance analysis aims on checking whether specified tolerances enable functional and assembly requirements. The tolerance analysis approaches discussed in literature are generally assumed without the consideration of parts’ form defects. This paper presents a new model to consider the form defects in an assembly simulation. A Metric Modal Decomposition (MMD) method is henceforth, developed to model the form defects of various parts in a mechanism. The assemblies including form defects are further assessed using mathematical optimization. The optimization involves two models of surfaces: real model and difference surface-base method, and introduces the concept of signed distance. The optimization algorithms are then compared in terms of time consumption and accuracy. To illustrate the methods and their respective applications, a simplified over-constrained industrial mechanism in three dimensions is also used as a case study. [ABSTRACT FROM AUTHOR]

In tolerancing analysis area, the most various existing approaches do not take form defects of parts into consideration. As high precisions assemblies cannot be analyzed with the assumption that form defects are negligible, the paper focuses in particular on the study of the form defects impacts on the assembly simulation and that by comparing two optimization algorithms (iHLRF and Quapro). The study is limited firstly to the cylinders. For the optimization, two main types of surfaces modelling are considered: difference surface-based method and real model. The compared models allow assessing the non-interferences between cylinders with form defects, potentially in contact. This is in the main issue to validate a tolerance analysis approach. [ABSTRACT FROM AUTHOR]