Today I'm talking about nodes. 0.4 is the first version of Revolution engine that allows us to work with some kind of hierarchy. This means that both in 2D and 3D subsystems, every entity (panels, buttons, objects, lights, cameras, etc...) is at the same time a node in space (either 2D space or 3D space). This way you can use the same functions to move a camera, an object, a light, whatever. Futhermore, nodes let us attach some objects to others and simplify move functions so much(because child nodes alwais move relatively to their parents, instead of in the absolute space). Let's see some examples:
-You can attach a camera as a child to the player, and the camera will automatically follow that character.
-You can attach wheels to a car and so, when the car moves wheels will move. But at the same time you can make the wheels rotate respect to the car. Later you can de-attach the wheels when you blow up the car and throw them far away ;)
-You can create a complex 2D menu for your game, made of many panels, buttons and texts, all of them attached to a single node, or to differents nodes that are also attached to a single node. This way you can show or hide the whole menu just by showing or hiding the parent node. Just one instruction to hide or show hundreds of panels.
I'm sure you can imagine so many more uses for this feature ;)