Working on...

Silently the project is growing. Recently some important changes are added to the core classes.

First, I add some support to the core objects to emit signals, for example when an object are added or removed from a group, or when some property (like color or line width) are changed. That brings more independency between the core and the UI. The later can react when receive a signal and, in the case of folders, new objects are added automatically.

Second, I have modified some presentation elements: defining the items of the menus and toolbars and finding appropriate icons for the explored. Also I modified the windows to definitively work in SDI (Single Document Interface) mode.

Finally, and this is a very important concept, I have added time support to the core objects. Now it is possible to set a time of validity to an object, including the camera itself. Given a period to be shown by the camera and a set of object (with or without periord of validity, independently) the camera's actual time advances step by step showing the object that are valids in the specified time position.
Now, I am working of the way to show the time line to the user: show the current visualization time (the cursor), indicate which objects are visible at the cursor position, and so on.