hello,

There are many shader types such as Plastic,Constant,etc. These shader has little parameters and almost can do nothing in production.
These days vopmaterial is used for almost all situations. I don't know why these shaders still exist. And they make many confusing for teaching to students.
Are they for compatible or any other use?

Thanks.

I would say they are legacy components left in tact for optimization. Spout that to your students and they will seem to be impressed.

The Mantra Surface is an incredible memory hog. Add a few images maps to it and you will quickly find your graphics card and viewport display overloaded.

For instance, the Constant shader renders blazingly fast. If I am doing a piece for design work that needs rendered at print sizes it is ideal.