How to > Delete 2D and 3D
  
Delete 2D and 3D
You can delete (or remove) unwanted elements and objects at any time during the design process. Note that this actually removes the object from the design. If you want only to hide the object, see Show and hide.
To delete 2D elements
1. Click 3D Access and then, in the Utilities group, click Delete 2D.
2. Specify the elements you want to delete using one of the following:
Click the elements.
Box the elements. (If you box both geometry and construction geometry, boxing will select the geometry elements first and delete them. If you want specific construction items to be deleted, either pick them individually or use the Select tool.)
Use the Select tool to specify multiple elements or specific types of elements.
3. You can specify other elements to delete or click to complete the operation.
To delete 3D objects
1. Click 3D Access and then, in the Utilities group, click Delete 3D.
2. Specify the objects you want to delete, using one of the following ways:
Click the objects.
Select the object on the structure browser.
Enter the object's name.
Use the Select tool.
3. You can specify other objects to delete or click to complete the operation.
* 
It is not possible to reload an assembly file if you delete parts which already form part of that assembly.
Learn more
If you make a mistake, you can undo a command using Undo One on the Quick Access Toolbar.