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

Related Work2.1. Data Flow ModelsThis visualization system was one of the first systems having a visual programmingeditor in combination with several modules. Figure 2.11 shows an example of OpenVisualization Data Explorer c○ IBM (OpenDX) with the visual programming editor on theleft side and the created image on the right side.Let’s take a closer look at the data flow in figure 2.11. Modules consist of inputs,displayed as boxes on the upper side of the icon, and outputs, shown as boxes on thelower side of the icon. The importer loads data into the system and is connected tothe RubberSheet object. The RubberSheet object creates a 3D height field from the 2Ddata. The output of the RubberSheet object is branched to the AutoColor and the Iso–Surface object. The AutoColor object calculates a color map. The Iso–Surface objectgenerates the white contour lines. The output of AutoColor object and the Iso–Surfaceobject are merged by the Collect object that is linked to the Image object.One disadvantage of the visual programming approach is, that it is difficult to keepthe general view in larger projects, because of the huge number of icons andconjunctions between them.Although OpenDX is a Open Source project not much progress was made in therecent years, especially in comparison to VTK (see section 2.1.7 on page 18), which isOpen Source project too.2.1.6 Open Inventor [1992]Figure 2.12: OpenInventor example scene graphOpen Inventor 8 is an object–oriented rendering toolkit based in IRIX Inventor 9 bySGI. Open Inventor uses a scene graph data flow model. A simple scene graph consistsof a directed acyclic graph with nodes connected by edges. The scene graph is traversedfrom the root node using a depth–first–search order and a left–to–right convention onthe same level.8 Open Inventor TM by SGI c○ [SGI]9 The IRIX Inventor TM file format was first released in July 1992 by SGI c○16