Hi Neha,

I’m not sure I understand your question. In a simple case of total internal reflection (TIR), if the rays come at an incidence angle smaller than the critical angle, then they are not reflected. Instead, they are refracted.

Do you want to filter out the refracted rays?

In any case, I’ve made a simple example of a point source emitting in a cone of 50 degree from within a rectangular volume of N-BK7:

This is what the layout looks like without filters:

As you can see, some rays are refracted and make it out of the rectangular volume (green segments), and the other rays get reflected (TIR) inside the rectangular volume.

If you just want to see the rays that get reflected, the filter string (found in the settings of your Layout diagram under Filter) is Rn with n being the object that the rays are reflected upon, in my case the rectangular volume in 1:

R1

This is the result in the 3D layout:

Notice that the filter string is also shown in red in the bottom-right corner of the 3D layout.

If instead you use the filter string Tn with n the object that the rays are transmitted through, in my case the rectangular volume in 1:

T1

You get the following result:

Note that these filter strings can also be applied to the Analyze..Ray Database Viewer except the field is called Apply Filter this time.

I hope this helps, and take care,

David