SDS is an acronym for Solutions Development System, a C/C++ language interface compatible with the ADS? (AutoCAD? Development System) interface found in other CAD systems. SDS provides hooks into IntelliCAD, allowing you to create custom applications. SDS communicates with the user and IntelliCAD via LISP (akin to the way that ADS works with AutoLISP? and other CAD systems). However, SDS greatly augments the capabilities found in LISP with a much more powerful command base that can also access the operating system. This allows you to create even more sophisticated custom solutions. And, because SDS applications are compiled, they are typically faster than LISP applications.