Iterated Calculations and Summing ARNs

Size: px

Start display at page:

Download "Iterated Calculations and Summing ARNs"

Maximillian Bradley
5 years ago
Views:

1 Iterated Calculations and Summing ARNs INTRODUCTION This knowledge base article discusses how to iterate calculations and sum the results in the ARN (Analysis Results Node) via a script. One reason why this might be useful is that when tracing a large number of rays, tracing in batches and summing the results after each step might be more time efficient. This will be particularly suited to illumination models where a very large number of rays are required to obtain statistically good data. This example script sums both the Irradiance and color image data and then stores the resultant ARNs in the Analysis Results folder on the FRED tree and also as.fgd files in the current directory. SCRIPT EXPLANATION The script IteratedCalculationsAndSummingARNs.frs is structured as follows: Lines 23 26: User Settings. Here the number of loops, the number of rays (per run, per source) and the Analysis Surface at which the data is to be calculated are defined by the user before the script is run. If the displayfirstlastcharts flag is set to True then the results of the first step and the final step will be displayed in the chart view. Lines 37 47: Configuring the sources.

2 Here the script loops over all entities in the Tree and all sources are re configured to use the number of rays defined in the User Settings. Additionally, each source is power normalized according to the number of loops so that the total power contributing to the final data set at then end of the iteration loop is consistent with the initial source power settings. Note that it is assumed that each source has Ray Position Type = Random Plane. Lines 55 56: Naming the ARN files. For convenience we choose that the filenames will be the "[total rays] rays" e.g. "10000 rays." Lines : Performing the calculations and summing the results.

3 For each iteration of the loop, the rays are traced and two ARNs are created, one for the irradiance (IrradianceToARN function), and one for the color image data (ColorImageToARN function).

On all but the first iteration, these newly created ARNs are combined with the previously accumulated data using the

For convenience, lines 107 108 print the status of the run in the FRED text window.

ARNWriteToFile subroutine. The files are saved with the names [numrays] rays irradiance and [numrays] rays colorimage.

4 On all but the first iteration, these newly created ARNs are combined with the previously accumulated data using the ARNLinearCombination subroutine and then deleted to save memory. For convenience, lines print the status of the run in the FRED text window. Lines : Saving the ARN files The Irradiance and color image files are saved to the current directory using the ARNWriteToFile subroutine. The files are saved with the names [numrays] rays irradiance and [numrays] rays colorimage. Lines : Resetting the power of the sources to the original state. After completion of the script you will see that ARNs have been created in the Analysis Results folder on the FRED Tree, and the fgd files have been created in the current directory.

5 The fgd files can be loaded into the Document at any time in the future by right clicking on the Analysis Results folder on the Tree and selecting "Create New ARN From a File..." EXPANDING THE SCRIPT To demonstrate the procedure, this script uses functions to sum Irradiance and color image data. It is important to note that this process is not limited to these two datatypes and that other ARN functions can be used to sum other types of data. For example the LuminousIntensityToARN function can be used to store in an ARN the luminous intensity collected on a DAE Analysis Surface.

Rotating Prisms with Scripting

Rotating Prisms with Scripting INTRODUCTION This knowledge base article will describe how to set up an embedded script that rotates two prisms, traces a source at each rotation position, and calculates