One characteristic of our approach is that the three levels (Overview, Explore and Experience) contain significantly different details. These are modelled in the same way as levels or scenes in a computer game and hence a mechanism for moving between these levels is required. In a computer game the transition is triggered by game play events, such as completing a race or eliminating all enemies, however in our case we need something more user driven.
In addition, the amount of modelling effort varies greatly across the levels, this means that the coverage of each level will vary considerably. It is expected that 100% of an area will be modelled at the Overview level but Explore and Experience will be restricted to areas of particular interest. It is assumed that the user will stat at the Overview Level and thus begin with a 100% view of the area modelled but we need a way of identifying the areas where the more detailed levels exist and a way of transitioning to them.
The first transition of this type that we have addressed is between the Overview and Explore levels. There are of course many possibilities for transitions here but as an initial Proof of Concept we used a method we call transition spheres. These are blue spheres, or domes, that are placed on the model to indicate where the Explore levels are located. These spheres may be turned on or off by the user with the default being off to ensure the initial view of the model is not too cluttered.
Explore Spheres shown on the model
The sphere is centred over the point where the user is placed on the Explore Level. As the user moves the mouse over a particular sphere it changes colour to indicate that it may be clicked. It is also possible to display a text box with information about the location at this point. When the sphere is clicked a message is displayed to show that the Explore level is loading and then the user is placed on the model at the correct location.
Highlighted and Clicked Explore Sphere
The user can move back to the Overview Level at any time by pressing the “E” key. At present this returns the user to the home position with the full model in view, although this could be changed to return back to the point the model was entered from.
Player transitioned to the Explore Level with option to return to Overview
This is just the first type of transition that we have implemented and many others will be necessary, for example between Explore and Experience and different Explore areas. We are working on these and will cover in future posts.