Topicscape 3D mind mapping structure explained
Here is a quick illustration of how Topicscape represents a multi-parent hierarchy, with an emphasis on the structure. It is just a beginning of a Topicscape that you might construct when organizing some information about Modes of Transport.
If your cursor is not over the picture below, it shows the names of the topics decided on by the person who built this collection of information.
The Current Topic (CT) is the main one in the view at any time - in the picture below it is Automobiles. Any topic can be made into the Current Topic, which will be the one you chose as your area of investigation at the time. It might be something like "To Do now", or "Marketing Reference". Behind it are its parents; to its left are sibling topics. The surrounding ones provide context and spread your search if required, but the Current Topic's children, grandchildren and so on in front of it, allow you to focus down and narrow your search.
A quick look back at 2D
Below is the same organization of topics in 2D. 2D mindmaps cannot make some of the connections that 3D Topicscape allows: Like multiple parents for a topic, and loose associations.