Analysis On Moulded Bra Cup Surface Feature And Its Model Base Building

Based on its good wearability, moulded cup bra is popular among female consumers and occupies a large market. At the same time, higher requirement for bra comfort and functionality makes bra design and manufacture more difficult in underwear enterprises. According to related survey, there are some problems in moulded cup bra design and production: first, without corresponding database based on design principle, bra design depends on existing cup models that have not been analyzed and organized effectively, which results in lacking product design innovation, efficiency reducing and cost increasing. Also, to meet some functional requirement, 3D curve and surface modification and wearing experiments are need to be done repeatedly. Furthermore, in order to solve metioned problems, it is necessary to improve the efficiency of moulded bra cup design and save design cost. As a result, moulded bra cup surface features are analyzed using reverse engineering technology in this paper.The research related contents and methods in this paper are as follow:(1) Some problems are put forward according to the in-depth understanding on moulded bra cup reverse design which is acquired through internship and survey in underwear enterprises and literature reading.(2) First the 3D moulded bra cup models are built in the reverse engineering environment. The related experiments are conducted: The moulded bra cups which have same cup size 75 B and different shapes are selected to obtain point cloud data through 3D Ca Mega projection grating measuring technique with binocular CCD camera, and data pretreatment and model reconstruction in the Geomagic and Imageware software environment fast and accurately.(3) Moulded bra cup geometric modeling feature abstraction is made, which includes:abstraction of moulded bra cup BP by cone fitting according to cup point cloud data,abstraction of section-feature curves in the vertical, horizontal, ±45° direction respectively and abstraction of bra cup capacity according to bra cup capacity concept.(4) The method of “replacing surface by curve” is used to analyze the curvature of bra cup surface section-feature curves. Moulded bra cups samples are classified into four typesby Euclidean distance similarity method and hierarchical clustering method, which is verified the same as the categories of inner bra cup surface. Then, the feature of inflection points and peak points on moulded bra cup surfaces and curves are analyzed based on the classification results. Furthermore, two basic outer surface of moulded bra cup are built according to their curvature similarities of cup curves and their differences in cup height and top cup curve style. Besides, four types of inner cup surface features are present by analyzing section-feature curve in different directions respectively.(5) Moulded bra cup model base is built based on UG/OPEN GRIP in UG software,which includes basic outer surface model, inner surface section-feature curve model and top cup curve model. Moulded bra cup parameter design is achieved according to different styles and functional requirements in moulded bra cup design.Analysis on mouldedba cup surface and curve, model classification in a certain degree provides scientific basis and more information for outer and inner surface design.