You can customize IntelliCAD by adding custom programs written in any of several programming languages that run within IntelliCAD, including LISP and Solutions Development System™ (SDS). With IntelliCAD, you can run many programs originally created for use with AutoCAD. Specifically, you can use programs written entirely in AutoLISP with no modification.
IntelliCAD supports the AutoCAD dialog control language (DCL), which is used by AutoLISP functions to define the look of dialog boxes. You can use all DCL files unmodified within IntelliCAD.
To write applications in C or C++, IntelliCAD uses SDS, a C/C++ language interface compatible with the AutoCAD Development System (ADS) interface in AutoCAD.
For more information about adding custom programs to IntelliCAD in one of the compatible programming languages, click the appropriate link here.
Visual Basic for Applications(VBA)