# Core Objects

Core Objects are the smallest sub-objects that are useful to the Authors who wants to develop a structural element in the library. The objects that the authors will develop in the library should be developed with the help of the objects specified in the **ParamML** standard object library specified under this title.

**ParamML** core objects can be classified into the 8 categories listed below.

* Basic Core Objects (Unit Object, Repeat Object, Export Object, Extends Object, Private Object, Group Object)
* 3D Geometric Objects
* Alignment Object
* CAD Objects
* Finite Element Object
* Specification Control Object
* Document Objects
* Interface Objects

The **PARAMML** core can be extended for various purposes with additional objects.