Unlike other MMEs that were written essentially to do one thing, Ray-MMD can do many things. Because it is a system rather than merely an effect, it gives the user a lot of latitude and freedom. Unlike most MME packages, Ray-MMD is an environmental lighting system. There are good articles on this site on how to use the effect at a more advance level, but if you have never used the effect before, it is best to start here. You really need to know a little bit about what the effect is suppose to do and how it works. We will not discuss the theories nor technologies underlying the effect, except for the basics. This article will give you the basic steps on how to set up the effect and get it working. Beginner’s Guide to Using Ray-MMD ver 1.5.0 Part of the problem is that the effect comes with next to no beginner’s instructions and most of the tutorials on how to use the effect on YouTube are not particularly helpful either. It also seems to be one of the hardest for many new users to MMD to get working.
Ray-MMD is one of the most popular MME shaders currently available.