PCAD+

Classification of categories of elements followed in Revit Structure is based on their usage.  Revit Structure uses five classes of elements: Host Host are elements categories that form the basic structure of a building model and include model elements such as structural walls and floors. Components Components are the elements that are added to host elements or act as stand-alone elements such as doors, windows, and foundations. Components are used to model building elements that are usually delivered and installed on site, such as doors, windows, furniture, and so on. Components are instances of loadable families and are hosted by other elements, which are instances of system families. For example, a door is hosted by a wall, while a freestanding component such as a desk is hosted by a floor or a level. Annotations Annotations are the 2D; view-specific elements that add content to the project documentation such as dimensions, tags, text notes, and so on. ...

The changes they’re making  Autodesk is gradually transitioning new software purchases of our products to subscription options only. After 31 October 2015, perpetual licenses of the following Autodesk® AutoCAD LT® Family products will no longer be available for sale in selected Asia Pacific countries ( Bangladesh, Bhutan, Brunei, Cambodia, China, Hong Kong, India, Indonesia, Korea, Laos, Macau, Malaysia, Maldives, Myanmar, Nepal, Philippines, Singapore, Sri Lanka, Taiwan, Thailand and Vietnam ): Autodesk AutoCAD LT Autodesk AutoCAD LT for Mac® Autodesk Inventor LT™ Autodesk Revit LT™ Autodesk AutoCAD® Inventor LT™ Suite Autodesk Revit LT™ Suite Customers who purchased perpetual licenses, of Autodesk AutoCAD LT Family products before 31 October 2015, will be able to continue to use that license. Customers who have a perpetual license with Maintenance Subscription (US site) will receive software updates and corresponding benefits for as long as the subscription remai...