QuickStart Guide - Tasks and Tools

## 3.8 Tasks and Tools

The following examples illustrate a number of techniques and tools that are helpful in using Data Explorer.

### Adding Captions

The `Caption` tool allows you to control the placement, font, size, wording, and other aspects of a caption in the Image window.

1. Open visual program `.../Caption.net`.
2. Select `Open All Control Panels` in the `Windows` pull-down menu. A control panel appears.
3. Select `Execute on Change` in the `Execute` pull-down menu. When the image appears, note that the caption at the bottom of the Image window is the same as the name of the realization technique shown in the control panel.
4. Click on the option button in the control panel and select `Streamlines`. Both the image and the caption change accordingly.

Use the `Caption` configuration dialog box to change the placement and font size of the caption.

1. Double click on the `Caption` icon to open the configuration dialog box and click on the `position` toggle button.
2. Clear the `position` parameter field and type "0 1".
3. Click on `OK`. The caption moves from its default position to the top left corner of the Image window.

   Note: [0 0] specifies the bottom left corner and [1 1] the top right.

4. Reopen the Caption configuration dialog box and click on `Expand` to show the hidden parameters.
5. Click on the `height` toggle button.
6. Double click on the associated parameter field to highlight the value there.
7. Type a larger value in its place (e.g., if the value was "15," type in "20").
8. Click on `OK`. The caption type changes size. (See "Displaying and hiding parameters".)

To change the wording of a caption, you must use the `Format` tool:

1. In the VPE window, disconnect the `Caption` input from the `Selector` interactor.
2. Select `Annotation` and `Format` in the palettes.
3. Position the `Format` icon between `Selector` and `Caption` and open the configuration dialog box.
4. Drag the cursor over "(none)" in the `template` parameter field and then type "Visualization Method: %s" in its place (%s indicates that a string will be inserted).
5. Click on `OK`.
6. Connect the second output tab of `Selector` to the second (middle) input tab of `Format`.
7. Connect the `Format` output to `Caption` and reexecute the visual program. The caption reads "Visualization Method: Streamlines."

   See Caption and Format in IBM Visualization Data Explorer User's Reference.

### Adding Input Tabs to Tool Icons

Tools such as `Compute`, `Options`, and `Switch`, among others, can have a variable number of inputs. If you need more tabs than the number shown by a default icon, you can increase the number:

1. Select the tool icon to which you want to add tabs.
2. Select `Input/Output Tabs` in the `Edit` pull-down menu and select `Add Input Tab` in the cascade menu. An input tab is added to the icon.
3. Repeat Step 2 as many times as necessary.

Note: You can also remove tabs from a tool icon by following the same procedure, but select `Remove Input Tab` in Step 2.

### Connecting Scattered Data Points

Many Data Explorer modules cannot be used with scattered data points that have no connections (i.e., interpolation elements). However, Data Explorer does provide two methods for creating connections between scattered data values.

1. The first method uses the `Connect` module.
   - Open and execute visual program `.../Connect.net`.

     The scattered data values in the image are created by the `Construct` module. The `Connect` module uses triangles to connect them.

2. The second method uses the `Regrid` module.
   - Open and execute visual program `.../Regrid.net`.

     The data values here are the same as those in the `Connect` example. They are mapped onto a regular grid by the `Regrid` module. The rightmost `Construct` module generates the grid.

   See Connect and Regrid in IBM Visualization Data Explorer User's Reference.

### Controlling Execution with Switch

`Switch` allows you to decide which portions of a visual program are executed (e.g., whether a data set is visualized with `Isosurface` or `MapToPlane`).

1. Open visual program `.../Switch.net`.
2. Select `Execute on Change` in the `Execute` pull-down menu. The image that appears is a streamline representation of the data set.
3. Select `Open All Control Panels` in the `Windows` pull-down menu. You can now use the selector interactor to switch from one visualization to the other.

You can modify the selector interactor and increase the number of choices.

1. Double click on the interactor to open the `Set Selector Attributes` dialog box.
2. Double click on the `Value` parameter field and type "3" in that space.
3. Double click on the `Label` parameter field and type "MapToPlane." in that space.

   Note: The integer passed from `Selector` to the first input tab of `Switch` determines what input, if any, is passed on to another module. If the integer is "0" or greater than the number of objects being passed to the module, the output is NULL. Thus, "1" selects the first input (second input tab), "2" the second input (third input tab), and so on.

4. Click on `Add`. A new third line should appear under the first two.
5. Click on `OK` to close the dialog box. If you click on the option button in the selector, you will see that it now offers a third choice. Leave the control panel open.

The third choice shown in the Selector, however, is not yet operative (select `MapToPlane` in the control panel and reexecute the visual program). To implement this choice, you must incorporate a third visualization in the program, such as that represented by the program segment on the right side of the VPE canvas. This segment computes a MapToPlane of temperature data.

1. Click on the `Switch` icon to highlight it.
2. Select `Add Input Tab` in the `Edit` pull-down menu. A new input tab is added to `Switch`.
3. Connect the first ("mapped") output tab of the `AutoColor` icon (below the MapToPlane icon) to the new input tab of `Switch`.
4. Select `MapToPlane` in the control panel and reexecute the visual program. The `MapToPlane` visualization appears in the Image window.

Note: Switch selects among inputs. The corresponding module that selects among outputs is Route. Both are described in IBM Visualization Data Explorer User's Reference.

### Controlling Inputs: Configuration Dialog Boxes

A configuration dialog box allows you to change the parameter values of a module. To open the dialog box, double click on the module's icon or single-click on the icon and select `Configuration` from the `Edit` pull-down menu. You can close the dialog box by clicking on `OK`.

#### Changing parameter values

A configuration dialog box displays the input parameters of a module.

You can change a parameter value by typing in a new value in the corresponding parameter field on the right side of the dialog box.

Note: If a tab is already connected to an arc, you must first disconnect the arc before typing in a new value.

#### Displaying and hiding parameters

Most configuration dialog boxes can be "expanded" to display "hidden" parameters for less commonly used functions. If a dialog box has hidden parameters, the `Expand` and `Collapse` buttons at the bottom of the box are enabled (i.e., their labels appear in solid type; otherwise, both labels are gray).

To display hidden parameters, click on the `Expand` button. To restore the dialog box to its previous state, click on `Collapse`.

Notes:

1. Whether a parameter is hidden or visible is determined by the associated toggle button in the `Hide` column of the dialog box.
2. The number of input tabs on an icon varies with the number of visible parameters in the dialog box.

### Controlling Inputs: Interactors

Using a configuration dialog box to specify tool inputs can be awkward, especially if the inputs are changed frequently or if the number of inputs is large. A simpler means of controlling input values makes use of interactors, which appear only in Control Panels. They are represented on the VPE canvas by stand-ins, or icons, selected from the category and tool palettes just as tools are. The output of an interactor, like that of any tool, can be connected to one or more inputs.

For this part of Tutorial II, you will use a scalar interactor stand-in to control an isosurface value. A scalar interactor can control any parameter that accepts a scalar value as input. Other types of interactor (e.g., vector, integer, string) can control parameters that take the corresponding type of input.

Begin by opening visual program `.../Isosurface3D.net.`

#### Selecting interactors and placing stand-ins

The procedure here is essentially the same as that for selecting tools and placing icons (see "Selecting tools and placing icons").

1. Select `Interactor` in the categories palette.
2. Select `Scalar` in the tools palette and position the cursor (now an inverted "L") above `Isosurface`.
3. Click again. The stand-in for the `Scalar` interactor appears.

#### Connecting the interactor

1. Click and hold on the `Scalar` output tab and drag the cursor to the middle `Isosurface` input tab (which lights up when the cursor touches it).
2. Release the mouse button to establish a connection (represented by a rectilinear black line) between the two.

#### Creating a control panel

Double click on the `Scalar` icon. A control panel appears containing a scalar interactor labeled `Isosurface value`. Stepper arrowheads can be used to change this value.

#### Setting the interactor attributes

To set interactor attributes, you must open a `Set Attributes...` dialog box by:

- double clicking on the interactor in the control panel or
- selecting `Set Attributes...` in the `Edit` pull-down menu of the control panel.

When the dialog box appears, you are ready to (re)set the attribute values:

1. Click on the `Maximum` field. The value disappears.
2. Type `1` and press `Enter` to set the new value.
3. Repeat Steps 1 and 2 for `Minimum`, and change the value to `.1`.
4. Repeat Steps 1 and 2 for `Global Increment` and change the value to `.01`.
5. Repeat Steps 1 and 2 for `Decimal Places` and change the value to `2`. (You can also reset this value with the stepper buttons.)
6. Click on `OK`. The dialog box closes.

When the minimum and maximum values are set, Data Explorer will prevent values outside that range from being entered.

Note: As discussed in "Data-driven Tools", data-driven interactors derive their own minimum and maximum from the data itself.

#### Executing the program on change

1. Select `Execute On Change` in the `Execute` pull-down menu of the VPE menu bar.
2. Use the right-hand stepper arrowhead in the interactor to increase the isosurface value. As the value changes, so does the image in the Image window.

   Notes:

   1. You can also change the isosurface value by clicking on it, typing in a new value, and Pressing Enter.
   2. You can accelerate the value change by holding down the mouse button after selecting a stepper arrowhead.
   3. If you change values faster than Data Explorer can generate images, it will complete processing the current value and then "jump" to the one most recently specified, passing over any intermediate values.
3. Click on the left-hand stepper arrow to decrease the value. Again, new images appear in the Image window.
4. Select `End Execution` in the `Execute` pull-down menu.

#### Changing the interactor style

In this example, you will change the interactor style from "stepper" (as in the preceding example) to "slider."

1. Click on the scalar interactor `Isosurface value` if it is not already highlighted.
2. Click on `Set Style` in the `Edit` pull-down menu of the control panel. Another pull-down menu appears.
3. Click on `Slider`. The interactor changes appearance.
4. Select `Execute On Change` as in the preceding example.
5. Using the left mouse button, drag the slider tab to the right or left to increase or decrease the isosurface value.
6. Release the mouse button to generate an image corresponding to the new value.
7. Select `End Execution` in the `Execute` pull-down menu.

#### Changing the interactor label

The default label of an interactor connected to a tool is the name of the tool followed by the name of the input parameter: in this case "Isosurface value."

1. Click on the `Isosurface value` interactor if it is not already highlighted with a white border.
2. Click on `Set Label...` in the `Edit` pull-down menu. The `Set Interactor Label...` dialog box appears.
3. Double click on the `Interactor Label` field or drag the mouse cursor over the text.
4. Type in a new name and click on `OK`. The dialog box closes and the new interactor label appears in place of the previous one.

   Note: You may break the label into two or more lines by typing `\n` where you want the desired line break(s) to appear.

### Creating Animations

This example demonstrates a few ways of using a sequencer.

1. Open (but do not execute) visual program `.../Animate.net`.
2. Select `Sequencer` from the `Execute` pull-down menu. Note that both the Loop and Palindrome buttons in the control panel are already activated (recessed).
3. Click on the Forward button (>): the visual program executes. The Image window opens and the image begins to run continuously through an "animation" sequence in which a data slice changes position.
4. Click on the Stop button (&sqbul;).
5. Disconnect the leftmost `AutoColor` icon from `Image` and connect the left output tab of the other `AutoColor` icon to `Image`.
6. Click on the Forward button (>) again. The animation sequence shows a set of streamlines growing longer and then shorter and then repeating the process.
7. Disconnect `AutoColor` from `Image` and connect `Isosurface` to `Image`.
8. Click on the Forward button (>). The sequence is that of a continuously changing isosurface.
9. Click on the Stop button (&sqbul;) to halt the sequence.

See Sequencer in IBM Visualization Data Explorer User's Reference.

Note: In this example, a transmitter and several receivers are used to make "invisible" connections between tools. The frame tool below the `Sequencer` icon is a transmitter. The other frame tools are receivers. Receivers and transmitters belong to the `Special` category of tools (see IBM Visualization Data Explorer User's Reference).

#### Changing the limits of the sequencer

1. If the sequence is still running, click on the Stop button (&sqbul;) to halt it.
2. Click on the ellipsis button (`...`) in the `Sequence Control` panel to open the `Frame Control` dialog box.
3. Click on the `Max` parameter field, type in "30," and then press Enter.
4. Click on the Forward button (>) to start the sequence. The isosurface sequence now proceeds to larger isovalues (smaller isosurfaces).
5. Close both control panels by double clicking on the top left button of the `Sequence Control` box.

For Future Reference
`Min` and `Max` control the minimum and maximum number of frames that a sequencer can generate. `Start` and `End` are set by default to the same values, but they can take any values in the range. The `Increment` parameter controls the difference between output values (frames).

### Creating and Using Macros

Macros are collections of tools that can be represented by a single icon in the VPE canvas. Macros thus allow you not only to simplify the appearance of your visual program but also to share commonly used functions between programs. This section briefly introduces the basic concepts of creating and using macros. (The topic is treated in detail in IBM Visualization Data Explorer User's Guide.) The general procedure for creating a macro follows on the next page.

1. Decide how many inputs and outputs your macro will have.
2. For each input, select `Special` in the categories palette and then `Input` in the tools palette.
3. Position the mouse cursor in the VPE canvas and click once to generate an `Input` icon.
4. Repeat Steps 2 and 3 for `Output`.
5. Open the configuration dialog box for each tool to give it an appropriate name, description, and default value.
6. Select any additional tools you want to include in the macro and place their icons on the canvas.
7. Connect the `Input` and `Output` icons to the appropriate tools.
8. Select `Macro Name` in the `Edit` pull-down menu and name the macro.
9. Save the macro.

For Future Reference
To use the new macro, you must first load it into Data Explorer: select `Load Macro` from the `File` pull-down menu. Once loaded, the macro will be available from the tools palettes. Simply select it and place its icon on the canvas. For descriptions of the inputs and outputs specified when the macro was created, open its configuration dialog box. To see the component contents of the macro, click on the icon to highlight it and then select `Open Selected Macro` in the `Windows` pull-down menu.

The following example illustrates the use of a macro in a visual program.

1. Select `Load Macro` in the `File` pull-down menu.
2. Type `/usr/local/dx/samples/tutorial/SampleMacro.net` in the `Filter` field at the top of the dialog box and press Enter. The name of the macro appears under `Files` on the right side of the dialog box.
3. Click on the macro name to highlight it, and then click on `Load Macro` at the bottom of the dialog box. A new category appears in the categories palette: `Macros`.
4. Select the new category. The name of the new macro appears in the tools palette. Now you can open a visual program that uses this macro.
5. Open and execute visual program `.../UseSampleMacro.net`.

   Although the visual program looks simple, the image it produces is quite elaborate.

6. Click on the `SampleMacro` icon to highlight it and then select `Open Selected Macro` in the `Windows` pull-down menu. A new window appears, displaying the "network" of `SampleMacro`: This macro performs various operations on the output from three `Input` modules (top) and feeds the result to a single `Output` module (bottom). It is this output that is fed to the `Display` module in the visual program.

### Data-driven Tools

Many of the tools in Data Explorer can be "data driven". That is, their attributes (e.g., limits) can be determined dynamically at run time from the data set being used.

Note: The attributes of data-driven tools become effective only after the first execution with the new data set.

#### Data-Driven Colormap Editor

1. Open and execute visual program `.../DataDrivenColormap.net`. The image is a color-mapped slice of data, with a color bar at the top of the Image window.
2. Select `Open All Control Panels` in the `Windows` pull-down menu and change the `Selector` value to `wind`.

3. Reexecute the visual program. The color map changes to reflect the new data set.

See Colormap in IBM Visualization Data Explorer User's Reference.

#### Data-Driven scalar interactor

Scalar, integer, and vector interactors can all be data driven. The example here is that of a scalar interactor.

1. Open and execute visual program `.../DataDrivenScalar.net`.
2. Select `Open All Control Panels` in the Windows pull-down menu and change `Format value` to `cloudwater`.
3. Leave the control panel open and reexecute the visual program. The `Isosurface value` (along with the image) is updated to reflect the new data set.

See Scalar in IBM Visualization Data Explorer User's Reference.

#### Data-driven selector

In this example, the input from `Import` to the `Selector` interactor is a data group consisting of two fields.

1. Open and execute visual program `.../DataDrivenSelector.net`. The image is a temperature field.
2. Select `Open All Control Panels` in the `Windows` pull-down menu.
3. Select `wind_velocity` in the control panel and reexecute the visual program.

The control-panel options `temperature` and `wind_velocity` are derived from the field names of the imported data.

In this network, `Inquire` determines whether or not the data set is "vector" and, if so, `Include` excludes invalid data values. If the data is not vector, the path followed goes directly from `Select` to `Switch`.

See Selector in IBM Visualization Data Explorer User's Reference.

#### Data-driven sequencer

In this example, the limits for the `Sequencer` are set automatically according to the number of elements in the `x`-dimension of the data set (as determined by the `Inquire` module).

1. Open (but do not execute) visual program `.../DataDrivenSequencer.net`.
2. Select `Sequencer` from the `Execute` pull-down menu. Note that both the Loop and Palindrome buttons in the control panel are already activated (recessed).
3. Click on the Forward button (>): the visual program executes. The Image window opens and the image begins to run continuously through an "animation" sequence of two dozen frames.
4. Stop the animation sequence by:
   - Clicking on the Stop (&sqbul;) or Pause (`||`) button, or
   - Clicking on the Loop and Palindrome buttons to deactivate them.

See Sequencer in IBM Visualization Data Explorer User's Reference.

### Modules: Using AutoColor

The AutoColor module automatically colors data for you. By default, it colors data from blue (for minimum values) to red (for maximum values).

1. Open and execute visual program `.../AutoColor.net`. The image is a translucent isosurface and a colored plane.
2. Select `Sequencer` in the `Execute` pull-down menu and click on the Forward (>) button in the `Sequence Control` panel. The colors represent wind data.
3. Click on the Stop button (&sqbul;) before proceeding.

Because `AutoColor` colors each plane individually, the full blue-red range is used each time to represent the wind variation in a single plane. As a result, the same color in different planes can represent different data values and different colors can represent the same value. In order to make the color representation consistent from plane to plane:

1. Connect the output tab of the rightmost `Import` icon to the second (projecting) input tab of `AutoColor` ("min").
2. Click on the Forward button (>) of the Sequencer again. `AutoColor` now applies the blue-red range to the entire data set, so that the same color values consistently represent the same data values in every plane.
3. Open the `AutoColor` configuration dialog box and click on `Expand` to show the hidden parameters. (See "Displaying and hiding parameters".)
4. Click on the `opacity` toggle button and change the value in the parameter field to ".3."
5. Click on the Forward button (>) of the Sequencer again and note the change in the plane.

See AutoColor in IBM Visualization Data Explorer User's Reference.

### Modules: Using Compute

`Compute` is a general purpose module for performing algebraic, trigonometric, and logical operations on data. It can also extract components from vectors, create vectors from scalar components, and cast between different data types.

1. Open and execute visual program `.../Compute.net`. The image represents wind velocity over the surface of the earth. Color values are based on the magnitude of the wind velocity, and the small black squares and rectangles represent missing data.
2. Disconnect `Include` from `AutoColor` and connect the output of `Compute` to `AutoColor` instead.
3. Execute the visual program. Now the colors are based on the absolute value of the x-component of the wind velocity.
4. Double click on the `Compute` icon to open the configuration dialog box. In this example the module has a single input (`wind`), and the operation to be performed is to determine the absolute value of its x-component.
5. Change "abs(wind.x)" in the `Expression` field to "abs(wind.y)." and reexecute the visual program. The image changes accordingly.

Note: `Compute` is not limited to a single input, and input tabs can be added with the `Add Input Tab` function in the `Edit` pull-down menu (see "Adding Input Tabs to Tool Icons"). By default the inputs to `Compute` are labeled a, b, c,..., but you can rename them.

It is also possible to use `Compute` on components other than `data`. For example, suppose you wanted to display a regular 2-D grid of latitude and longitude on a spherical surface. You could use `Compute` to convert the x,y positions of latitude and longitude to x, y, and z positions of a spherical surface. For an example, open and execute visual program `.../WarpedGrid.net`, which generates two entirely different objects (in separate Image windows) from the same data.

See Compute in IBM Visualization Data Explorer User's Reference.

### Modules: Using Map

The `Map` module maps one field of data onto another. The field to be mapped to is the first parameter; the field to be mapped from, the second parameter. In the most common use of this module, no other parameters are set: the positions of the first field are used as indices to the positions of the second; the associated data values from the second field are then mapped as new data values onto the first.

Components other than `positions` and `data` can also be mapped to one another.

1. Open and execute visual program `.../Map.net`. In this example, wind values are mapped onto an isosurface of cloud-water quantity and the result is colored. In addition, wind values are mapped onto a probe point and displayed as text glyphs.
2. Double click on the right-hand `Import` icon to open its configuration dialog box. The `name` parameter field contains a file name ending in "wind".
3. Change "wind" to "temperature" and click on `OK`.
4. Reexecute the visual program. The image is now a color map of temperatures on the isosurface. The number displayed is the data value of the probe point.
5. To move the probe point, first select `View Control` in the `Options` pull-down menu.
6. Next select `Cursors` in the `Mode` pull-down menu. The probe point appears as a small white square immediately to the left of the data value.
7. Drag the probe point to reposition it, and then release the mouse button. The data value is updated and displayed next to the newly positioned probe point.

See Map and Probe in IBM Visualization Data Explorer User's Reference.

### Modules: Using Plot

`Plot` creates a 2-dimensional plot from x,y data. (Data Explorer expects the "positions" component to contain the x-values, and the `data` component the y-values. You can pass (import) a group of such fields to `Plot`, which plots them as multiple lines. You can also add data-point markers to the lines.

1. Open and execute visual program `.../Plot.net`. Two Image windows appear: one a color map of elevation data for the southeastern United States; the other, a plot of the elevations along the purple line shown in the color map. (The `Slab` module extracts the elevation data along the line, but `Construct` could have been used to create the line and `Map` to map the elevation data onto the line. Note that `Compute` is used to extract only the x-component of the positions.)
2. To animate the line:
   1. Select `Special` and `Sequencer` in the palettes.
   2. Position the `Sequencer` icon above `Slab`.
   3. Double click on the icon to open the `Sequence Control` panel and then single-click on the ellipsis button (`...`) to open the `Frame Control` dialog box.
   4. Set `Min` to "0" and `Increment` to "5."
   5. Click on the ellipsis button again to close the `Frame Control` dialog box.
   6. Double click on `Slab` to open its configuration dialog box.
   7. Click on the `position` toggle button to deactivate it (the associated parameter field will read "(all)") and then on `OK`.
   8. Connect the `Sequencer` output tab to the third input tab of `Slab` ("position").
   9. Click on the Forward button (>) in the `Sequence Control` panel.
3. The limits of the plot change somewhat from frame to frame because they are based on the line given for each frame. To make the limits constant:
   1. Double click on the `Plot` icon to open its configuration dialog box.
   2. Set the `corners` toggle button on and change the values in the parameter field to {[260, -6000][290, 2000]}.
   3. Click on `Expand` (to show the hidden parameters) and then on the `font` toggle button (to change the font to "roman_tser").
   4. Click on `OK` at the bottom of the dialog box.
   5. Click on the Forward button in the `Sequence Control` panel.
4. To place data-point markers on the data plot:
   1. Disconnect `Plot` from `Unmark`.
   2. Connect the `Options` output tab to the first ("input") tab of `Plot`.
   3. Reexecute the visual program. The markers appear as small open circles.
   4. To see what options were specified, double click on the `Options` icon to open its configuration dialog box. In this example, the "mark" attribute is set to "circle" and the "mark every" attribute is set to "10." Thus every tenth data point is marked with a circle.

See Plot in IBM Visualization Data Explorer User's Reference.

### Processing Images

A variety of image processing functions are available with the `Compute`, `Filter`, and `Overlay` modules. A few of these functions are demonstrated in this example.

1. Open visual program `.../ImageProcessing.net`.
2. Select `Open All Control Panels` in the `Windows` pull-down menu. The control panel displays two selector interactors:
   - The first specifies which of three filters is to be applied to the data.
   - The second specifies which of four image-processing functions is to be performed. (Note that only the first two of these functions is affected by the options selected in the first interactor.)
3. Select `Execute on Change` in the `Execute` pull-down menu. You can now select these different functions and observe their effects.

### Saving and Printing Images

Once you have created an image, you can save it to a file or send it to a printer. (See also IBM Visualization Data Explorer User's Guide.)

- If your visual program uses the `Image` tool (as the programs in this tutorial do), you can select `Save Image` and `Print Image` in the `File` pull-down menu of the Image window.

  When saving an image, you can choose among several formats and specify the final image size or the resolution. Similarly, you can choose format and size or resolution before printing an image on your local printer (with a command such as: `lpr -Pmy_postscript_printer`).

- If you are not using Image, you should use the WriteImage tool (`Import and Export` category).

  However, you will have to create the image with Render and display it with Display (both are from the `Rendering` category).

  Connect the output of Render to the first input tab ("input") of WriteImage. Specify the format and size, using the parameters described under WriteImage in IBM Visualization Data Explorer User's Reference.

[ OpenDX Home at IBM | OpenDX.org ]