Adjusting the Scalar

One application of volume rendering is for visualizing the distribution of scalar quantities that represent combustion products.

In the reference tutorial, the Soot Density function provides an estimate of the amount of soot that a room fire generates. The function is defined with a built-in conversion to mg/m^3 as:

${Passive Scalar}*$Density*1000*1000
For this tutorial, the function is modified to compute soot density in kg/m^3, so that a custom unit can be applied afterward in the scalar scene:
  1. Select the Automation > Field Functions > Soot Density node.
  2. Set the Dimensions property to Mass/Volume.
  3. Set Definition to ${Passive Scalar}*$Density.
Create a custom unit:
  1. Right-click the Tools > Units node and select New > Units.
  2. Rename the Units_1 node mg/m^3.
  3. With the mg/m^3 node selected, set Conversion to 1.0E-6.
  4. Set Description to mg/m^3.
  5. Set Dimensions to Mass/Volume.
To get a sense of the range of the scalar, use the scalar displayer.
  1. Open Scenes > Scalar Scene 1.
  2. Edit the Scalar Scene 1 > Scalar 1 > Scalar Field node and set the following properties:
    Property Setting
    Function Soot Density
    Clip Off
    Units mg/m^3
    Min 300.0
    Max 800.0
    The scalar scene now shows an approximation of the scalar variation in the volume.