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

Software Design3.5. General CashFlow UML Diagramrefers to the MultiData node. A sample scene graph is shown in figure 3.10 onpage 51 containing all three data nodes.• Data Consumer nodesare nodes handling data. The Data Consumer node is an abstract interface only.Data Consumer nodes can be subdivided into:– Loader nodes inserting data into a data node and therefore have write accessonly.– Mapper nodes accessing data which is processed by algorithms generatingnew data. Accordingly these nodes have read and write access.– Render nodes are defined as nodes reading data only and generating images.In general no other data output is created.All Data Consumer nodes link either to a DataAccess node only or to a DataAccessnode and a Grid node, if topology of the grid is also requested by the algorithm.• Traversal state objectsare the third group of objects handling traversal state changes while processingthe scene graph.Note, that traversal state objects are not part of the scene graph but store attributesduring the scene graph traversal.– Data node elementsused for implicit linking of nodes and for dynamic linking between Multi-Data nodes, DataAccess nodes and Grid nodes.– Refinement elementskeeping parameters for grid resampling and interpolation refinement likefor instance used by streamline integration algorithms.– Update Actionto specify, when a loader node should reload the data or an asynchronousmapper node should process the data.In the following sections all nodes will be described in detail.3.5.1 Example for CashFlow Scene GraphIn the previous section the scene graph was simplified, because not all nodes and conceptshad been introduced at that time. In section 3.2 on page 42 a simplified scenegraph was used in combination with the visualization of abstract data mapped onto apolar and a Cartesian grid (see figure 3.2 page 42 ).Figure 3.10 on page 51 shows the correct CashFlow scene graph to figure 3.2page 42. Node (1) is a MultiData node charged by a Loader node (4). The Loaderalso sets new values in the DataAccess nodes labeled (2) and the defines the type of50