The Research And Implementation Of 3D Modeling Technology For Creative Design

3d models are widely used in film,television,animation,games and other fields.Especially with the popularization of 3d printing technology,more and more common people has personally modeling requirements,but most 3d modeling systems are hard to get start.How to express the designer's creative idea directly and easily,it is the main problem in the 3d modeling technology,especially for novice.In order to solve this problem,this paper presents a free shape 3d modeling prototype system,used in creative design.The work of this paper is divided into three main parts.First of all,it is the representation method of surface.The surface representation of this system based on improved Catmull-Clark subdivision,the sharp edge concept is introduced on the quadrilateral mesh,then edge-vertices and vertex-vertices corre-spond to new calculation formulas.Relatively the original subdivision rules keep smooth effect everywhere,the improved subdivision rules can achieve piecewise smooth effect,which is suitable for the actual design application.Secondly,it is editing operation of surface.Editing operations are four main cat-egories:intelligent selection,which effectively reduces number of mouse clicks;geo-metric deformation contains common rotation,translation,zoom;topology modifica-tion can construct handle bar and other structures quickly;feature marking is used for marking sharp edge.All operations base on the control mesh,and they are representa-tive,simple and practical.In the end,it is the conversion of surface type.The mainstream of 3d modeling systems adopt the non-uniform rational B-spline surface(NURBS)as a representation,under the detail design.So our system provides the function of surface conversion for creative design result's reuse.The surface conversion process as follow:quadrilateral region partition uses relationship between the control mesh and the result mesh to seg-ment,the method is simple and efficient;then look for long edge in the quadrangle area,we use cubic B-spline curve to fit long edge and interrupt this curve at corner place later,as the constraint of surface fitting to maintain the regular boundary smooth-ness;finally we use bi-cubic B-spline surface,combined with curve constraint,to ap-proximate each quadrilateral area,then adjust the smoothness around singular vertices.In order to verify the advantages of the proposed system,a few experiments were carried out.First,expert designer and novice designer were invited to use this system to build the specified models,both finished in a short time and time are close.Then,expert designer was invited to use different prototype systems to build the specified models,by contrast,the proposed system is more conveniently and accurately to ex-press the designer's idea.