In EJS 3.0 , there is no differentiation between 2D and 3D elements.
For example: particle,arrow elements can be added under 2D drawingPanel or 3D drawingPanel.
All those elements had properties for x,y,z even you only use it as 2D element.

It has been changed later, there are 3 parts under "elements for the view"
1. Interface: you can add the top drawing frame, drawing panel from here, and other control elements (button, slider...)
2. 2D drawables: all the elements has to be added under [b]2D drawingPanel [/b]or [b]2D plottingPanel[/b].
3. 3D drawables: all the elements has to be added under [b]3D drawingPanel[/b].