Postprocessing of Continuum Analysis > Visualizing Scalar Data by Iso-surface and others > Curve plotting of scalar data

 

Curve plotting of scalar data

Curve plotting is a method of re p resenting the data distribution along a specified line in the form of graph. This method is supplementary to contouring, and should be preceded by contouring. Curve plotting converts a contour image into graphical representation. The data values along a specified line are extracted and plotted in the form of graph, which gives, in some cases, more descriptive and more detailed information than contour lines do. Curve plotting can be applied to contour images on any plane or surface including cut plane and parallel planes. Numerical data can also be viewed using the curve plotting. This function is available for both 2-D surfaces and 3-D volumes.

< Curve plotting >

> Initiating curve plotting

Curve plotting is initiated by choosing "Curve Plot" item from menu . Then, "Curve Plot" window appears on the screen, and menu is attached on the menu bar. A bounding box surrounds the model rendered in the main window, and the initial state of the sampling line is drawn across the bounding box. The curve plot is displayed on "Curve Plot" window, for the initial setting. Prior to initiating curve plotting, a contour image should be displayed. Data of the contour image becomes the subject of the curve plotting.

> Modifying curve plotting

At the time curve plotting is initiated, "Curve Plot" window contains a graph representing the magnitude of the data value along the sampling line initially set by the software. This curve plot can be modified or adjusted by further interaction in the main window and "Plot Window" Most importantly, a new plot can be obtained by moving the sampling line. The sampling line can be moved and slanted by using mouse click and drag by the following steps:

 

1) Set the menu items as desired.
 

menu has items related with controlling of sampling line and plotting update. This is explained in detail in the later part of this section.
 

2) Place the screen cursor on one end of the sampling line, and press the mouse button.
 

The color of the sampling line is altered, indicating that the sampling line is selected.
 

3) Drag the end of the line with the mouse button pressed.

 

The end of the line moves along with the cursor, and accordingly the position and the direction of the line are changed. The graph on "Curve Plot" window is updated as soon as the sampling line is modified.
 

4) Double click an edge of the bounding box to change the direction of the sampling line quickly.

 

Double clicking an edge of the bounding box induces one end of the sampling line positioned on the center of the edge, and the other end on the center of the opposite edge.

> Displaying the numerical value at the sampling point

A point on the sampling line can be designated as the sampling point. Click one point on the sampling line. Then, the sampling point is set at the point, and indicated by    mark. The numerical value of the data on the sampling point is displayed in a character string on "Curve Plot" window. The relative location of the sampling point over the sampling line is indicated by hair lines and a character string on "Curve Plot" window as shown in the above figure. The sampling point can be moved along the sampling line interactively by using mouse drag. While the point is being moved, the numerical value is updated continuously together with the mark of the newly positioned point.

> Resizing the graph

The graph is drawn to fit the plotting window. Thus, the size of the graph can be changed by resizing the window. Click the bottom right corner of the window, and drag. Or, click the zoom box of the window. Then the graph is resized to fit the new window frame.

> Setting the options for curve plotting

When curve plotting is initiated, menu appears on the menu bar. The menu has items related to controlling the sampling line and updating "Curve Plot" window. 

 

Controlling the movement of the sampling line.
 

The movement of the sampling line is controlled in the manner set by the menu items in menu.
 

- "No Constraint" : The sampling line moves without constraint. While one end of the sampling line moves, the position of the other end is not altered. This is the default setting.
 

- "Orthogonal" : The sampling line is always positioned orthogonal to the edges of the bounding box, while one end of the line is repositioned.
 

- "Diagonal" : If one end of the sampling line moves along an edge of the bounding box, the other end moves in the opposite direction, so that the line rotates.
  - "Parallel" : The sampling line moves in parallel. If one end of the line moves, the other end also moves the same distance.

Setting the update of "Curve Plot" window.

The graph on "Curve Plot" window may be updated dynamically while the sampling line is being moved by dragging. Or, the graph may be updated only when the movement of the sampling line is completed by releasing the mouse button. This option can be set by checking or unchecking "Dynamic Display" item in menu.

> Terminating curve plotting

Curve plotting is terminated by clicking the close box at the top left corner of the "Curve Plot" window, or by initiating any other function. The bounding box and the sampling line disappear from the main window at the moment the "Curve Plot" window goes away. menu also disappears from the menu bar.