The Design And Development Of CASS Parametric Drawing System

Water supply and drainage in the field of engineering, AutoCAD works with its powerful graphics processing power is widely used, the graphics rendering highly generic, but in a particular field of expertise has not yet functional. In recent years, with social and economic development, water supply and drainage as the main body of water supply plant and wastewater treatment plant design appeared in a rash, the design quality and efficiency of water plant structures are higher and higher required,in traditional design methods, designers spend a great deal of time to look-up table, computing, graphics, but also to remain in the CAD as a "drawing board" in the initial stage, there is no realization of parametrization mapping, the parametrization design of water treatment structure is the effective way to improve the design quality, efficient.This article is based on CAD for the second development platform, using visual interface and ActiveX Automation technology,using VBA programming language which embedded in the AutoCAD develops a set of auxiliary class type setting chamber’s parametrization design system. The parametric design process include:parameter and structure dimention input interface, structure calculation program modules, graphics and calculations showing program modules, the visual interface and program modules are linked by program statement,realized the transfer of data and users interactive.This parametrization design programme of sedimentation tank,including:VBA secondary development of technology; sedimentation tanks standardized design; management interface module; sedimentation tank design module; parametric drawing module. VBA as a second language development tools, powerful, complete computing precipitate process, called CAD drawing of all orders. Process to the size and structure of variable size as a driver, the graphics obtained through the procedures of the various points of coordinates, the coordinates of the points will be given to CAD command, to be completed by the graphic layout, when the input variables of different sizes can be drawn in different size Sedimentation tanks graphics.According to the angle,elevation,diameter and other parameters as variables, according to the pipeline anchor relative to the benchmark calculated the location of the coordinates can be drawn based on user input a variety of point of view, the diameter of the graphics pipeline. Slice angle and elevation decide profile of the graphic layout, graphics program can access points coordinate value of the profile information, enter a different cutting variables, the profile can be mapped graphics. This procedure is to use VBA programming language computing precipitate out of the process size pool, and then process the size, structure, size, the user enters the relevant information can be spread to all related graphics program, drawing on its procedures for the completion of the organization coordinates of the points calculation and graphics generation, This will in the CAD environment for the preservation of graphics, printing, exporting, and the menu in the form of procedures for release.Each constituent of the software is realized by virtue of the window and the module way.Through the passable menu, the button and the click of the mouse,the function of each module is realized,and the parametric drawing is completed.This paper includes five parts. Chapter1introduces the background of the topic, its significance, its research status at home and abroad and what it concerns on; Chapter2introduces development tools of the system and author’s development ideas; Chapter3states the basic theories of auxiliary class type setting chamber’s; Chapter4detailed the methods of parametric drawing; Chapter5states on the paper’s conclusions and advices for further reseach to others.