Mesh Simplification

The following tables and images show how mesh simplification, specifically converting large Uniform Grids into Triangulated Irregular Networks, can significantly reduce rendering time with only a slight decrease in model quality. The mesh simplification algorithm can reduce the mesh to a specified quantity or quality goal. For a quantity goal, the number of triangles or the number of vertices can be specified. For a quality goal, the average or maximum vertical error can be specified.

Ethiopia Model Original Model - Uniform Grid Simplified Model - Triangulated Irregular Network
Number of Vertices 262,144 5,079 (1.93 %)
Number of Triangles 522,242 10,000 (1.914 %)
Average Vertical Error 0.0 0.0916 (0.34 %)
Maximum Vertical Error 0.0 0.2843 (1.07 %)
Drawing Time for Textured Model(O2 R10000, 128MB RAM) 1.798 seconds 0.068 seconds (3.78 %)
Mesh Simplification Time (O2 R10000, 128MB Ram) n/a 22 seconds

The following two images show a wireframe and texture model of the Ethiopia data set.

Ethiopia wireframe model

Ethiopia textured model


Grand_Canyon-west Digital Elevation Model from the USGS Original Model - Uniform Grid Simplified Model - Triangulated Irregular Network
Number of Vertices 1,442,401 14480 (1 %)
Number of Triangles 2,880,000 28800 (1 %)
Average Vertical Error 0.0 0.037 (0.93 %)
Maximum Vertical Error 0.0 0.134 (3.33 %)
Drawing Time For Wireframe (O2 R10000, 128MB RAM) 3.453 seconds 0.132 seconds
Mesh Simplification Time (O2 R10000, 128MB Ram) n/a 164

The following image shows the Triangulated Irregular Network model of the Grand Canyon model.

Grand Canyon TIN


Hurricane Andrew Model Original Model - Uniform Grid Simplified Model - Triangulated Irregular Network Another Triangulated Irregular Network
Number of Vertices 1,048,576 50,000 (4.77 %) 10,000 (0.95 %)
Number of Triangles 2,093,058 99,896 (4.77 %) 19.958 (0.95 %)
Average Vertical Error 0.0 0.026 (0.56 %) 0.107 (2.23 %)
Maximum Vertical Error 0.0 0.176 (3.66 %) 0.754 (15.65 %)
Drawing Time for Textured Model(O2 R10000, 128MB RAM) 6.9 seconds 0.663 (9.6 %) 0.144 seconds (0.208 %)
Mesh Simplification Time (O2 R10000, 128MB Ram) n/a 180 seconds 173 seconds

The followin two images show wireframe and texture map modes for Hurricane andrew with 10,000 vertices.

Hurricane Andrew wireframe

Hurricane Andrew textured


Hurricane Fran Model Original Model - Uniform Grid Simplified Model - Triangulated Irregular Network
Number of Vertices 466,804 25,000 (5.36 %)
Number of Triangles 930,860 49,835 (5.35 %)
Average Vertical Error 0.0 0.111 (1.75 %)
Maximum Vertical Error 0.0 0.367 (5.77 %)
Drawing Time for Textured Model(O2 R10000, 128MB RAM) 2.987seconds 0.316 seconds (10.579 %)
Mesh Simplification Time (O2 R10000, 128MB Ram) n/a 73 seconds

The following two images show wireframe and texture map modes for Hurricane Fran.

Hurricane Fran, Wireframe

Hurricane Fran, Textured


Jeremy Hinegardner
Last modified: Mon May 24 13:19:12 CDT 1999