CashFlow, A Visualization Framework for 3D Flow - Studierstube ...

Results5.5. Grid Iterator Examples5.5 Grid Iterator ExamplesAs proposed in section 4.5.2 on page 83 Grid Iterators can decouple the visualizationalgorithm from the grid representation. The advantage of that approach is, that thealgorithm can be applied to several grids without modifications. Also a new type ofgrid can be accessed by several algorithms by implementing the grid interface for thenew grid only. The disadvantage of that additional software layer is, that the executionspeed of the algorithms is decreased compared to algorithms using raw access to thegrids, taking properties of the grid into account.Two examples, figure 5.17 and figure 5.18 shows the use of grid iterators. The firstimage in figure 5.17 show the space shuttle data set rendered two times. The rearyellow part was created using two cutting planes and the from green part shows theinverse selection visualizing the rest of the plane. Note, that the data set is defined ona curvilinear grid. The visualization was created by iterating over the grid.The second example in figure 5.18 shows iso–volumes below a certain iso–valuerendered in red using the cuberille rendering style [LC85]. The image in the middle offigure 5.18 shows the inverted selection from the above image in red. The lowest imageillustrates the inverted selection again using a wire–frame visualization combined witha point–cloud rendering of all inner cells.As future work we plan to port the marching cubes algorithm by [LC87] to Cash-Flow creating a marching cubes grid iterator. Figure 5.19 shows a human skull generatedwith marching cubes rendered as IndexedFaceSet using an Open Source implementation.Figure 5.17: CashFlow Cutting Planes113