Hi Christabelle,

I’m not sure I understand your first question. You shall be able to type “N-BK7” in the Material column (the cell highlighted in your screenshot).

A surface doesn’t have a volume, therefore it doesn’t have a material associated with it. Some Objects, such as the Rectangle object, also describe a surface (in this case a rectangle surface) but if you try to type something in the Material column it disappears right away. However, you can change the coating and scattering properties of surface s in an object. To do that, double-click on the object of interest (this opens the object properties) and navigate to the Coat/Scatter tab.

The above is a screenshot from the Rectangular Volume object. For each surface, you can choose a Scattering model or define a coating, which can be one of the IDEAL coatings that for example mimic a perfect mirror.

Have a look at this article:

https://support.zemax.com/hc/en-us/articles/1500005578102-Introduction-to-stray-light-analysis-Part-3

I hope this helps.

Take care,

David

Hi David

Does this mean that the “MATERIAL” column of a NSC CAD object has no purpose ?

​@mocquin 

Apologies for the confusion.

The MATERIAL column of a NSC CAD object has definitely a purpose. As long as the object describes a volume (in the mathematical sense).

My answer was intended to answer the question: Can I assign different material to different surface?

Bottom line is that if an object is a surface (in the mathematical sense, not the OpticStudio surfaces), then indeed the MATERIAL column is not useful because a surface is infinitely thin and doesn’t have a need for a material. If you have an object that is a solid cube, then the MATERIAL column should be used to define its material.

Does that make sense?

Take care,

David

Thanks it seems clearer, but I’ve follow up questions regarding volumes then, I’ll open a dedicated thread