BricsCAD (Windows) Pro or higher


Bricsys provides a C/C++ API called the "BRX API". BRX stands for "BricsCAD Runtime eXtension". The BRX API is available for all supported product architectures and operating systems. Some features and capabilities are not available in all operating systems (see BRX API on Linux and Mac).

Code compatibility

BRX is source code compatible with ObjectARX, the standard C++ interface of AutoCAD. Plugin developers can use the same source code files to build separate binary modules targeting each CAD platform:

Note that it is not possible to load the same binary module on multiple platforms. A module compiled with ObjectARX cannot load in BricsCAD, and a module compiled with BRX cannot load in AutoCAD.


Following is a partial list of features and functionality supported by the BRX API:

Please note that this list is only a representative subset of the complete API.


BRX is source code compatible with recent ObjectARX versions, with some exceptions. Where possible, BRX supports both newer and legacy interfaces. In some cases, legacy interfaces have not yet been updated in BRX.

Compiling BRX applications

BRX modules, typically configured as unmanaged C++ extension DLLs, need to be compiled with the same platform toolset used for the target version of BricsCAD. This information and other details are provided in the BRX SDK itself:


A number of sample applications are installed as part of the main BricsCAD installation. In the API subfolder you can find:

  1. a BRX/C++ sample project that shows some features of the BRX API (custom entity, dockable dialog, ...). The sample contains build configurations targeting both BricsCAD and AutoCAD. The code can be compiled with the BRX SDK and ObjectARX, and the identical behavior can be checked on both CAD platforms.
  2. C# and VB.NET sample projects demonstrating the managed .NET API, including a C++/CLI mixed mode custom entity sample.

Quality Assurance

Bricsys has an extensive suite of automated tests to continuously monitor and test behaviors of BRX functions. Every function is checked for normal operation and error return values. In this way we can ensure correct behavior compatibility with the AutoCAD platform.


The BRX SDK consists of:

The BRX SDK is not installed with BricsCAD. The SDK is distributed as a separate download. Access to the BRX SDK is available free of charge to registered plugin application developers. Visit the Bricsys Developer Portal to learn more.

Note that the BRX SDK is not required for .NET plugin development. Plugins using the managed .NET API simply need to reference the desired managed assemblies installed along with BricsCAD. Those assemblies include:


Check the Bricsys Support Portal for answers to frequently asked questions and troubleshooting information.

Final notes

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