| China shoemaking industry is facing with a serious crisis.The traditonal manual production in workshop has not met economic development needs so that the present shoemaking procedure must be reform with advanced automatization technology.The last is extremely important in the shomaking technics since the design and maching quality of last affects the quality of shoes directly.So using CAD technology in the design and manufacture of last is the key and an inevitable trend of traditional last-making industry development.However, China's action is relatively slow in this field .So ,making research on this subject is very necessary and is of theoretic significance and practical value.This thesis is supported by national key project aimed at developing a practical shoe last CAD system which can combinate with the measuring devices and last-making machine to complete measuring,design and manufacture as to make products competitive on the basis of research results on shoe last CAD technology.At first this thesis analyzes the importance of developing CAD technology in shoemaking industry and introduces on the domestic and foreign technology's development status. According to analysis of general modeling technologies, this author put forward a discrete modeling method and gives strict definition, description and demonstration from mathematical point of view, which is the basis of last CAD technology. Moreove,on the condition that only surface data of shoe last is available, calculating methods of shoe size, girth and basic width are given.In order to realize the local deformation of last surface, The author developed a slop-based adaptive deformation(SAD) algorithm by analyzing deformation technologies of general object which decides the deformation intensity according to change of slope of grid curve on last surface. The outline of bottom of last is recognized in order to realize scaling of last. Then according to last design principle, methods about length scaling and girth scaling of last are given.On the basis of above algorithms, this paper gives the shoe last CAD system software developed by author. The software realized the main functions of shoe last CAD and established a database of shoe last. The main part of software is developed by Visual C++6.0 and OpenGL codes are embedded for getting the realistic display of shoe last. By integrating CAD and CAM software into one system and running test ,the results are satisfactory and may be applied to practical design and production of shoe last. |
