Gregory A. Turner

Real-time, continuous level of detail rendering of height fields

We present an algorithm for real-time level of detail reduction and display of high-complexity polygonal surface data. The algorithm uses a compact and efficient regular grid representation, and employs a variable screen-space threshold to bound the maximum error of the projected image. A coarse level of simplification is performed to select discrete levels of detail for blocks of the surface mesh, followed by further simplification through repolygonalization in which individual mesh vertices are considered for removal. These steps compute and generate the appropriate level of detail dynamically in real-time, minimizing the number of rendered polygons and allowing for smooth changes in resolution across areas of the surface. The algorithm has been implemented for approximating and rendering digital terrain models and other height fields, and consistently performs at interactive frame rates with high image quality.

4D symbology for sensing and simulation

The Armys Common Picture of the Battlefield will produce immense amounts of data associated with tactical goals and options, dynamic operations, unit and troop movement, and general battlefield information. These data will come form sensors (in real-time) and from simulations and must be positioned accurately on high-fidelity 3-D terrain. This paper is associated with the Armys 2-D symbols for operations and tactics so that the information content of this symbolic structure is retained. A hierarchy is developed based on military organization to display this symbology. Using this hierarchy, even complex battlefield scenarios can be displayed and explored in real-time with minimal clutter. The user may also move units around by direct manipulation, define paths, create or delete hierarchical elements, and make other interactions. To strengthen the capacity for distributed simulations and for using sensor information from multiple sources, DIS capability has been integrated with the symbology for dynamic updates of position, direction and speed, and hierarchical structure. This paper will also discuss how the techniques used here can be applied to general (non-military) organizational structures.

Theoretical Branching Ratios for the 5I7 -> 5I7 Levels of Ho3+ in the Garnets A3 B2C3O12 (A = Y, La, Lu, Gd; B = Al, Lu, Sc, Ga; C = Al, Ga)

A comparative study of triply ionized holmium in ten garnets is undertaken using the point-charge model to predict theoretical energy levels and temperature dependent branching ratios for the 5I7 to 5I8 manifolds.