A new architecture for efficient hybrid representation of terrains

Interactive visualization of highly detailed terrain models is a challenging problem as the size of the data sets can easily exceed the capabilities of current hardware. Hybrid representation of terrains tries to solve the problem by combining the advantages in terms of reduced size associated with multiple levels-of-detail of digital elevation models with the high quality associated with the triangulated irregular networks. However, as the measurements of both representations have different origins, a direct representation of the hybrid system would result in discontinuities.In this paper, we present an architecture for hybrid representation of terrains based on a local convexification algorithm. The architecture we propose permits the generation of the additional triangles required to join the models and thereby avoid the discontinuities. The architecture is simple and regular and a high triangle generation rate is achieved. Different optimizations have been performed that avoid waiting cycles between tessellator units and so increase the productivity rate of the system. Implementation results are shown for a Virtex-II FPGA as an application example.