Refining a Scalar Display

Typical considerations when rendering a scalar quantity are which contour style to apply, which color map to use, and whether to include visual artifacts from the mesh or geometry.

The scene must contain a scalar displayer with parts assigned, and a scalar Function selected for the Scalar Field node. Instructions for these steps and also for setting the color map are provided in Visualization Workflow.
Scalar fields are rendered using a series of contours, or bands, each of which represents a specific subrange of values within the overall range of values found in the scalar field. You can control how each band transitions to the next band as the scalar field is rendered on the part surfaces.
  1. To change the rendering of contours, select the [scalar displayer] node and set Contour Style to one of the options.
    • Automatic – contour style is set automatically based on the specified scalar function and parts
    • Filled – for finite volume meshes, rendered faces are filled with the scalar value stored at the center of the corresponding cell. For finite element meshes, the face-center value is reconstructed from the node values.
    • Smooth Filled – provides a smoothly varying field across a chosen number of levels (which you set on the Color Bar child node).
    • Smooth Filled + Line – adds isolines between the levels on a Smooth Filled plot. You can activate labels on the lines by selecting the Isoline Labels child node and activating Visible.
    • Line – shows only the isolines between the levels of a Smooth Filled plot, colored according to the interpolated value.
    • Smooth Blended – provides a similar plot to Smooth Filled, but using a computationally less expensive algorithm.
    If you choose Smooth Blended, also select the [scalar displayer] > Color Interpolation node and choose either Smooth or Banded. In some simulations, Banded gives a better result as it uses a 1D texture map for producing the bands.
  2. If you want to see the mesh lines on the parts selected for a scalar displayer, select the [scalar displayer] node and activate Display Mesh.
By default the list of field functions available for selection is filtered based on the representation selected for the displayer. You can change this setting manually.
  1. To change the filtering of available field functions using the color bar in the scene:
    1. Click the color bar in the scene, activating the Coloring Properties dialog.
    2. To make all field functions available in the list, deactivate the Filter by Representation checkbox.
    3. To filter the list based on another representation in the simulation, click Select to access the object selector.
    NoteThe changes to this setting are applied globally to the simulation, and are stored when the simulation file is saved.
By default the range of the scalar quantity is automatically based upon the range of the field function on the parts in the displayer. However, the range can also be set manually.
  1. To change the range using the color bar in the scene:
    1. Click the color bar in the scene.
    2. In the Range group box of the Coloring Properties dialog, enter the minimum value in the left field and the maximum value in the right field.


      Dimensions of the minimum and maximum fields are defined by the selected field function. The actual minimum or maximum value used can then be specified in any unit that matches these dimensions.

      Besides the ability to enter scalar values numerically, there is an open-ended range slider that can be used to adjust the scalar range. The visible range of the slider is dynamic and twice as large as the current scalar range, so the current minimum value is at 25% of the range and the maximum at 75%. This allows you not only to make the range smaller, but also larger. After each interaction with the slider, the handles snap back to 25% and 75%. So as the range increases, you can make bigger changes. And as it gets smaller, you can make more exact, fine-grained changes.

      If the Continuous Update checkbox is activated, the scene is updated while dragging the slider. If it is deactivated, it is updated once the mouse button is released.

      NoteThe changes to this setting are applied globally to the simulation, and are stored when the simulation file is saved.

      If you click Cancel, all changes are reverted. No intermediate "preview" changes are written to the Java macro.

      For a new displayer, the default clip mode is Off. Also, if Clip settings and Auto Range are off for either minimum or maximum, a "<" sign appears next to the value. This signifies that there are areas in the scene that are above or below this value, even though they share the same color.

      When viewing large geometries it is a good idea to deactivate Continuous Update. Also, in scalar displayers, banded contour modes need to recompute their geometry if the range changes, so in this case, continuous updates are also discouraged.

  2. To change the range using the object tree:
    1. Select the [scene] > [displayer] > Scalar Field node.
    2. In the Properties window, enter the minimum value under Min.
      This change causes the Auto Range property to switch to Max Value automatically, and the result appears in the scalar scene display. If you set the Max property first, the Auto Range property setting switches to Min Value.
    3. Enter a value for Max.
      The Auto Range property sets itself to Off, since you have manually set both values.
      If the manually entered range is smaller than the bounds of the scalar quantity, the contours are clipped by default.

    Alternatively, you can set the Clip property to Below Min to exclude only the scalar quantities below the range, or Above Max to do this with the quantities above the range.

    You can revert to the automatic range setting anytime by selecting Min and Max Values in the drop-down list of the Auto Range property.

When you add isolines to a scalar scene by selecting the Smooth Filled + Lines contour style, you automatically receive N - 1 isolines where N is the number of levels set in the color bar. However, if you activate labels for the isoline values, and you have a high number of levels, the isoline labels can become too dense for practical use.
  1. To display a smooth filled scene with a reduced number of isolines for the same value range:
    1. Select the [scalar displayer] node and set Contour Style to Smooth Filled.
    2. Select the corresponding Color Bar node and set a high number of levels, for example, 64.
    3. Duplicate the [scalar displayer] node using copy-and-paste:
      1. Right-click the [scalar displayer] node and choose Copy.
      2. Right-click the [scalar scene] node and choose Paste.
    4. Select the [copy scalar displayer] node and set Contour Style to Line.
    5. Select the corresponding Color Bar node and set a lower number of levels, for example, 16 (which is a multiple of the number of levels for the original displayer).
    6. To display the isoline labels, select the [copy scalar displayer] > Isoline Labels node and activate Visible.
    7. If you want to apply black coloring to the isolines, you can do so by applying a custom color map in the [copy scalar displayer] > Color Bar node. To achieve this effect:
      1. Select the [copy scalar displayer] > Color Bar node and set Color Map to grayscale.
      2. Next to the Color Map property, click (custom editor).
      3. In the Color Bar - Color Map dialog, click Edit a Copy.
      4. Set Name to Black Lines.
      5. On the color bar, select the color point on the bottom-right corner and click Delete. This change turns the whole color bar to a black fill.
      6. Click Close.