Unwritten procedural modeling with the straight skeleton

[摘要] Creating virtual models of urban environments is essential to a disparate range of applications,from geographic information systems to video games. However, the largescale of these environments ensures that manual modeling is an expensive option.Procedural modeling is a automatic alternative that is able to create large cityscapesrapidly, by specifying algorithms that generate streets and buildings. Existing proceduralmodeling systems rely heavily on programming or scripting - skills which manypotential users do not possess. We therefore introduce novel user interface and geometricapproaches, particularly generalisations of the straight skeleton, to allow urbanprocedural modeling without programming.We develop the theory behind the types of degeneracy in the straight skeleton, andintroduce a new geometric building block, the mixed weighted straight skeleton. Inaddition we introduce a simplifcation of the skeleton event, the generalised intersectionevent. We demonstrate that these skeletons can be applied to two urban proceduralmodeling systems that do not require the user to write programs.The first application of the skeleton is to the subdivision of city blocks into parcels.We demonstrate how the skeleton can be used to create highly realistic city blocksubdivisions. The results are shown to be realistic for several measures when comparedagainst the ground truth over several large data sets.The second application of the skeleton is the generation of building's mass models.Inspired by architect's use of plan and elevation drawings, we introduce a system thattakes a floor plan and set of elevations and extrudes a solid architectural model. Weevaluate the interactive and procedural elements of the user interface separately, findingthat the system is able to procedurally generate large urban landscapes robustly, aswell as model a wide variety of detailed structures.

[发布机构] University:University of Glasgow;Department:School of Computing Science

[关键词] computer graphics, straight skeleton, urban, procedural modeling