Auxiliary Dependent Variable
Use the Auxiliary Dependent Variable node to solve additional first-order ordinary differential equations for each ray released.
Auxiliary Dependent Variable
Enter a Field variable name. The default is rp and can be changed to anything provided it does not conflict with the name of the variables for the position or momentum degrees of freedom, or with other auxiliary dependent variables.
Enter a Source R. The unit of the source depends on the unit of the auxiliary dependent variable and the option selected from the Integrate list described below.
Select a way to Integrate the equation you have defined: With respect to time or Along ray trajectory. For example, to reproduce the variable for optical path length, you could set the Source to 1 and set Integrate to Along ray trajectory. To compute the length of the ray trajectory you can set the Source to 1 and set Integrate to Along ray trajectories.
Units
These settings are the same as for Accumulator (Domain).