View-dependent Adaptive HLOD: real-time interactive rendering of multi-resolution models
Rui Li · 2023
Real-time visualization of large-scale surface models is still a challenging problem. When using the Hierarchical Level of Details (HLOD), the main issues are popping between levels and/or cracks between level parts. We present a visualization scheme (both HLOD construction and real-time rendering), which avoids both of these issues. In the construction stage, the model is first partitioned (not cut) according to a Euclidean cubic grid, and the multi-resolution LOD is then built by merging and then simplifying neighboring elements of the partition in an octree-like fashion, fine-to-coarse. Some freedom applies to the simplification algorithm being used, but it must provide a child-parent relation between vertices of successive LODs. In the rendering stage, the octree-based hierarchy model is traversed coarse-to-fine to select the cube with the appropriate resolution based on the position of the viewpoint. Vertex interpolation between child and parent is used to achieve crack and popping-free rendering. We implemented and tested our method on a modest desktop PC without a discrete GPU, and could render scanned models of multiples tens of million triangles at optimal visual quality and interactive frame rate.