product focus
2012
by: Brian Benton
AutoCAD
Third-Party Apps for AutoCAD
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utoCAD® is a complicated and powerful design tool containing several hundred features, commands, tools, and settings. Users can create almost any type of design with this software, yet very often, they want even more tools—those that don’t come installed in AutoCAD. These tools might make drawing and modeling easier, provide features that AutoCAD doesn’t, make AutoCAD’s features easier to use. Regardless of why users want these added features, the fact is they do. Luckily, Autodesk has provided a means for users and companies to create them. These new or modified tools are often referred to as thirdparty applications.
What are Third-Party Applications?
Third-party applications are programs or routines designed to work inside another program or operating system, that are created by parties other than the creators of the host program or system. The ability to run third-party applications is one of the reasons AutoCAD rose to the top and became the premier CAD system. AutoCAD can run several different types of third-party software including .NET programs, .LSP routines, script files, ObjectARX, ActiveX, and others. AutoCAD makes it easy for “regular” users to create their own third-party apps through Visual LISP. Visual LISP, a programming tool for creating code in AutoCAD, is a form of the programming language LISP. Visual LISP is a full-featured programming language that can call AutoCAD commands, system 6
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variables, and dialog boxes in order to interface with the user. AutoCAD comes with a LISP writer inside; the files are saved in a .LSP file format. These files can be simple command macros or more complicated routines that create, save, and manipulate data. LISP files are so easy to use that users can drag and drop the file into AutoCAD to load it. The ObjectARX programming environment can be used to customize AutoCAD (and AutoCAD-based products) to gain direct access to AutoCAD’s database structure. It also provides access to the graphics system, command definitions, and object-oriented C++ programming interfaces. ObjectARX is a powerful tool that can be used to extend AutoCAD software. The ObjectARX SDK (Software Developers Kit) also includes a managed API, typically known as the AutoCAD .NET API. This API can use any .NET supporting language to further customize AutoCAD and its vertical platforms. The ActiveX can utilize COM automation. It can use VBAenabled applications such as Microsoft Office products. It can also be used from AutoCAD add-ins built using Visual LISP, ObjectARX, or the AutoCAD .NET API. There are many choices for developers who are interested in programming third-party applications for AutoCAD. Which ones are you familiar with? What are the needs and goals for the application?
June 2011