Namespace OpenMEPCad.Autocad

Block: A block definition containing a name and a set of objects. https://help.autodesk.com/view/OARX/2023/ENU/?guid=GUID-E6F7B03B-F5CC-4A18-9C48-BBF1D32A31FD

BlockReference: This .NET class wraps the AcDbBlockReference ObjectARX class. The BlockReference class represents the INSERT entity within AutoCAD. A block reference is used to place, size, and display an instance of the collection of entities within the BlockTableRecord that it references. In addition, block references can be the owner of Attribute entities (the list of which is automatically terminated by an SequenceEnd entity). Classes Derived from AcDbBlockReference. Classes derived from BlockReference must supermessage the base class's WorldDraw() function and allow it to do the work of drawing the entities in the block table record. This allows the osnap code to distinguish the graphics for each entity in the block table record and automatically get each entity's osnap points without having to iterate through the block reference.

Database: The Database object contains all of the graphical and most of the non-graphical AutoCAD objects. Some of the objects contained in the database are entities, symbol tables, and named dictionaries. Entities in the database represent graphical objects within a drawing. Lines, circles, arcs, text, hatch, and polylines are examples of entities. A user can see an entity on the screen and can manipulate it.