We propose a local model called moving multiple curves/surfaces approximation to separate mixed scanning points received from a thin-wall object,where data from two sides of the object may be mixed due to measurement error.The cases of two curves(including plane curves and space curves)and two surfaces in one model are mainly elaborated,and a lot of examples are tested.
Due to the shortages of current methods for the recovery of sharp features of mesh models with holes,this paper presents two novel algorithms for the recovery of features(especially sharp features)in mesh models.One algorithm defines an energy that is regarded as the difference between the initial features and the ideal features.The optimal solution of the energy optimization problem modifies the initial features.The algorithm has good performance on sharp features.The other method establishes a plane cluster for each initial feature point to obtain a corresponding modified feature point.If necessary,we can obtain the modified feature line by fitting these modified points.Both methods depend little on the result of fillingmodel holes and result in better features,which maintain the sharp geometric characteristic and the smoothness of the model.The experimental results of the two algorithms demonstrate their superiority and rationality compared with the existing methods.
In isogeometric analysis(IGA),parametrization is an important and difficultissue that greatly influences the numerical accuracy and efficiency of the numericalsolution.One of the problems facing the parametrization in IGA is the existence ofthe singular points in the parametrization domain.To avoid producing singular points,boundary-mapping parametrization is given by mapping the computational domainto a polygon domain which may not be a square domain and mapping each segmentof the boundary in computational domain to a corresponding boundary edge of thepolygon.Two numerical examples in finite element analysis are presented to show thenovel parametrization is efficient.
