How to create roughness and mask map / texture?

Hi guys,

Recently I study the materials of UE4. I know that the shading input value is depending on the input texture/map. For example, the character from Matinee Fight Scene has about five textures for each material: Roughness, AO, Mask, Detail Mask, Normal. Iā€™d like to know how to create the related textures, especially roughness, mask and detail mask. What is the most common method or tool to create them?

By the way, it seems the roughness and detail mask are created from the original diffuse texture using some tools. Also, can I think the specular texture is the roughness texture?

Thank you!

and

Second one is your best bet