CHAPTER 5	Ray Tracing

Introduction to Ray Tracing

Ray Tracing is the means by which TracePro simulates the distribution of flux throughout a model in analysis mode and at selected surfaces in simulation mode. This chapter contains the logic behind ray tracing in TracePro and the techniques you can use to enhance your raytrace.

How your rays interact with your model is partly determined by your model itself (the geometrical details of the objects you created and the properties you applied), and partly determined by how you control the rays being launched into your model. There are three basic methods of defining rays: Grid Sources, File Sources and Surface Sources.

Combining Sources

Sources are defined as Grid, Surface and File. Grid Sources are defined as virtual windows to a distant source with rays emanating from the window. Surface Sources are applied as a property to an object’s surface. File Sources are comprised of external ray data read by TracePro during the ray trace. Multiple types of each source can be defined and combinations of the three can be made to control the flux necessary to conduct a desired ray trace simulation.

Managing Sources with the System Tree

Each of the source types can be defined from the Define menu or by RightClicking in the Source tab of the System tree.

The Source tab in the System Tree (see page 1.5) acts as a central repository for all of the sources contained in the model. Each source is displayed as a node in a Source Tree. Expanding a node displays the various sources of each type and further displays the relevant data for each source. Each source node is preceded by a Green Check or Red X. Clicking on this flag will add or remove the source from the list of sources to trace.

Selecting a grid, surface or file source in the Source tab of the System Tree will cause it to be displayed in the Model Window. The displayed color of each source can be set when defining the source.

As an example, Figure 5.2 shows a model with the Source tab active in the System Tree. The Grid Source named “Grid Source 1” is selected and the boundary of the source is displayed in the Model Window. The Model also has a Surface Source defined but no File Sources. Both the Grid and Surface sources are enabled for raytracing since the Green Check is set.

Ray Tracing

FIGURE 5.1 - Source Tab displayed in the System Tree.

Managing Sources with the Source/Wavelength Selector

The Source/Wavelength Selector is available from the Raytrace menu. It displays a summary of all the sources and wavelengths in the model, and allows you to turn off and on individual sources and wavelengths. To turn off a wavelength or source, click on the green check-mark to change it to a red x. Figure 5.2 shows the Source/Wavelength Selector with two sources, one Grid Source and one Surface Source. The Grid Source has five wavelengths, and the Surface Source has two wavelengths. You can sort on Source Type, Source Name, or Wavelength by clicking on a column heading. Clicking on the heading a second time sorts the column in reverse order.

FIGURE 5.2 - Source/Wavlength Selector with two sources and seven wavelengths.

5.2	TracePro 5.0 User’s Manual