InnerSoft CAD for AutoCAD 2012 software (version 4.0) is a plugin for AutoCAD that allows users to perform various calculations and measurements within their AutoCAD drawings. The software includes tools for creating topographical sections, calculating volumes and areas, generating bills of quantities, and producing 3D models from 2D drawings. InnerSoft CAD also features the ability to import and export data in various formats, making it a versatile tool for engineering and construction professionals.