After some digging, I do have some experience with MDF. I would like to share them and you can post it anywhere, just credit me.
Note this article will be long since it's a bit complex. Do not waste time on it if you are not a modder.
Part 1. Basic
The first thing is you have to understand what is PBR. It's Physically Based Rendering textures. You can simulate most materials in the natural with a few texture maps. We're lucky since RE2 engine using it. That will make modding easier. The keywords are albedo/metallic/normals/roughness/ambient occlusion. I won't repeat them here but you can google them, there are a lot of tutorials in websites.
After you understand PBR, I suggest you use Substance Painter to do some testing. Like as aluminum/steel/chrome. They are a little different even they are all metal.
Part 2. Textures
For an outfit material, normally it includes 3 maps. ALBM, NRMR, ATOS.
For ALBM, you will put albedo to RGB and metallic to alpha. For some unknown reasons, the black in alpha is not a real black(0,0,0), it actually is 4,4,4. You will get material issues if you use 0,0,0.
For NRMR, you will put normals to RGB and roughness to alpha.
For ATOS, you will put alpha map to RED channel and ambient occlusion to BLUE channel. Normally, the GREEN channel used for other type material.
Part 3. Shaders
After you prepared all tex.10 files and put them to game. Sometimes you will feel dissatisfied or different from the effect in substain. That's because the parameters in the MDF file are incorrect. This requires you to understand the structure of the MDF file. I will use pl1000.mdf as an example to help you understand it.
Let's start with the file header. Remember that each shader has only four lines of headers.
Green, blue, cyan markers are all HEX addresses.
eg. 04 38 and B2 37, They are actually 3804 and 37B2. Press Ctrl+G and input 3804, you will find this 'pl1000_jacket.mat', and you will find 'mastermaterial/master/record_player.mmtr' in 37B2. This mmtr file should be a shader lib wrote by shader programmer. The MDF provide the parameters to let it work.
A complete shader consists of three parts (blue/yellow/Cyan). By compare, you can get the length of each part. eg. D728->D7C8, this is the length of the third part of 'pl1000_jacket.mat'. Obviously, 0478->05E0/1588->18B8/D728->D7C8 is a full shader of 'pl1000_jacket.mat'.
To be continued...