In the Non-Sequential Component Editor, insert a Null object as object #1 with all parameters set as default, then insert a Rectangular Volume object as object #2 referencing it to the previous object (-1 for Ref Object parameter). The reason for using a relative object reference (current object number -1) instead of simply giving the absolute reference will be apparent later when we duplicate the complete lightpipe.

Set the following parameters for the Rectangular Volume.

Ref Object: -1
Material: Acrylic
X1 Half Width: 5
Y1 Half Width: 5
Z Length: 20
X2 Half Width: 5
Y2 Half Width: 5
All other parameters: Default

To help us visualize the location and the orientation of the local axis to the object, double or right click on the Object Type column in the editor to open the Object Property window and check the Draw Local Axis box.



Open the 3D layout to see the object.

Insert new object (#3) and make the type Rectangular Torus Volume with the following parameters.

Ref Object: -1
Material: Acrylic
Outer R: 40
Inner r: 30
Start Angle:0
Stop Angle: 90
Thickness: 10
#Angle Facets: 20
All other parameters: Default

As mentioned in the beginning of this articles, the faceted representation of the Rectangular Torus Volume is for layout purpose only. For the raytrace calculation, the object is represented exactly by its equation to the full limit of the numerical precision in ZEMAX.

We now need to specify the appropriate X, Y and Z positions so that the Rectangular Torus Volume is in contact with the Rectangular Volume, regardless of the "Outer R" parameter of the torus. Remember, we will be varying the "Outer R" parameter later on to study the effect of light transmission.  We will use pick up solves to connect the two volumes and to make the "Outer R" – "Inner r" value to be always 10 mm. 

Set the following pick up solve on the "Inner r" parameter.




The first column after the “Material” column in the editor is parameter 1, which for the torus object is the "Outer R" parameter. This solve will make the "Inner r" value always 10 mm less than the Outer R parameter.

One end of the torus should contact the +Z end of the Rectangular Volume; you can make the "Z position" parameter of the torus the same as the "Thickness" parameter (parameter #3) of Rectangular Volume. Place the following solve on the "Z position" parameter of the Rectangular Torus Volume.