The primary structural entities you will find in a model or project that is linked/imported to 3ds Max from AutoCAD, Architectural Desktop or Revit are style-based objects (in ADT models), family elements (in Revit projects) or blocks (in both ADT and AutoCAD files). Each style-based object, family element, or block will most likely have many instances in the 3ds Max scene.
Instances are multiple occurrences of objects such as style-based objects or blocks that are clone instances. When you link a model or drawing that contains instanced objects to 3ds Max, those objects remain instances of one another.
Family Elements in a Revit project represent different items of a building and are separated into two general categories; Model and Annotation. The Model category includes such elements as walls, doors, windows and stairs while the Annotation category includes dimensions, text notes and section tags. When a DWG is exported from Revit and linked to 3ds Max, elements appear in the Modifier panel as Block/Style Parents, meaning you've selected the element at its topmost level, or as Linked Geometry, meaning one of the element's subcomponents.
Blocks are reusable objects made in AutoCAD or Architectural Desktop. Blocks are made of one or more objects that can be inserted into a scene at different locations, scales and orientations. Blocks can also be an amalgam of other blocks. A block that is made of other blocks is referred to as a nested block. Once linked to 3ds Max, blocks appear in the Modifier panel as VIZBlocks, meaning you've selected the block at its topmost level, or as Linked Geometry, meaning one of the block's subcomponents.
Note: If you use one of the “node hierarchy” Derive By settings, you will see Block/Style Parent objects in the Modifier panel and not VIZBlocks.
Architectural Desktop style-based objects are complex objects like Doors and Windows whose components rely on style definitions to control how they appear in the scene. For example, style definitions for a door set the type of door, the door thickness, the materials assigned to the various components, and so forth. Altering the style definitions changes the appearance of the object in the scene.