The Secondary Development Of AUTOCAD Based On Visual Lisp

In the mechanical design and manufacturing industry, with the graphics design software being introduced, the period that performs the simulation on the drawing board has passed. Now using professional graphics designing software is the basic skill for the designers. But how to make the design faster and more efficient has been raised up in front of the designers? In the mechanical industry AutoCAD is the most popular software. With the most updated AutoCAD software introduction by Autodesk, Visual Lisp's own language can address these problems.In this paper we make a secondary development on the AutoCAD software based on the Visual Lisp language so that mechanical and graphics designers would be able to focus on their work procedures and improve their work efficiency. This paper fulfills three major improvements:1. Enriching AutoCAD's features on graphics (a. Writing text and drawing graphics on the known inclined plane; b. Adding more features in the initialization settings; c. Automatically marking a circle on a single text line; d. Automatic marking roughness; e. Fast calculating the area of a closed curve); In the mechanical drawing, we find that AutoCAD always performs a lot of complicated and cumbersome steps and much slower than our hand drawing. These processing takes a lot of time with few benefits during our daily drawing. In order to solve this problem, we can put Visual Lisp into the operation on the corresponding procedures.In AutoCAD, Each object (such as a straight line, circle, text, block and point of view, etc.) has its own inherent attributes list; we can find out these attributes through some commands. After we obtain their property include important information (such as the type of target, the coordinates of the center, a radius of the size and the name of the drawing layer), we can modify these property or make use of these property2. Automatically generating standard parts drawing;In the mechanical parts drawing and assembly drawing, marking the surface roughness and drawing thread hole, bearings and bolts are tedious work. And since the variety of specification, size and series, the routine operation becomes very frustration. But we all know that they have common character. Just after a few parameters setting they can be found in the national standard for all other values. In terms of this character, we can prepare a number of standard procedures in the Visual Lisp in order to be able to complete the drawing very accurate and fast after enter some basic parameters. Also we can add magnification feature to make the drawing more convenient.3. Reading forms and applications and other data processing.In the mechanical CAD system, the data processing is very popular. We must operate the form storage, retrieval and transmission. As Visual Lisp language is good at dealing with table to store data and retrieve data, we can use Visual Lisp language to improve the efficiency in the AutoCAD systems.Here we develop the AutoCAD based on the visual lisp and integrate the Visual Lisp into AutoCAD. Engineers can use the Visual Lisp based AutoCAD to figure out their own operation. Making use of these functions in the mechanical drawing can make our work more convenient and improve our work efficiency.