I'm not too worried about these earlier rendering engines. For example, Corona relies on "reflection" and "refraction maps" as kind of a stand-in for the basic transmission properties of transparent and semi-transparent materials. Other rendering engines that we designed prior to the advent of PBR, of course, use different kinds of things to create a glass shader. These two rendering engines share a bunch of the basic transmission variables - IOR, Abbe, etc. Arnold is similiar in that it a "material type" of transmission at its core for the standard surface shader. That is, Maxwell Render has the two IOR variables, "Nd" and "K" and some others as a component of every material. These have a few "transmission elements or properties" at their core. There are several rendering engines that were and are inherently physically-based renderers, to my knowledge, Maxwell Render and Arnold.
![xvid4psp make input and output bitrate the same xvid4psp make input and output bitrate the same](https://support.audient.com/hc/article_attachments/115010332106/Screenshot_2017-06-22_15.10.32.png)
As you can see in my image illustration below, I can "create" information about the "transmission" variables of transparent materials such as glass in Substance Designer, but there's no good way to get this into other rendering engines. The most problematic issue in making and using "glass" materials in Substance Designer is the inability to transfer information about "transmission" properties of glass to other applications.