When setting up and using object classification, follow these guidelines for the best results:
Use only one object class definition file for a project. Object classes should be general enough that a definition for “roads” is appropriate in any circumstance. Create subclasses for freeways, parkways, small streets, and so on.
Only one person should edit object class definitions at a time, or one set of edits might be lost. If the definition file was just edited, quit AutoCAD Map 3D toolset and restart it to get the updated definitions.
Distinguish between the Object Type (on the Applies To tab of the Define Object Classification dialog box) and the Create Method (on the Class Settings tab). Object Type determines which existing objects you can add to this object class. If the object was not created with the selected method, you cannot add it. Create Method determines the method used to create new objects from this class (when you right-click the object class and choose Create Classified Object).
Note: If you plan to use this object class with objects from a drawing source, do not select more than one object type
Avoid renaming object classes, because this changes the name only in the object class definition file. Objects tagged with the object class name are unchanged. Since these objects point to a name that no longer exists in the object class definition file, the objects become undefined. You can search for undefined objects and update their object class name.
Avoid including styling options in object class definitions. For example, you can draw points using a block. You can specify that block if you use Block as the Create Method for an object class that represents point data. However, the block will not scale to the map, and might cause more work than it saves. Instead, create a drawing layer in Display Manager and assign the point objects to that layer. Style the layer from Display Manager using the desired block.