Most of the materials in real life can be modeled more precisely by using layers of different materials. Some layered surfaces can be analytically solved and converted into a single reflection model. However, vast majority of them cannot be represented this way. Therefore, representing arbitrarily layered materials is quiet challenging. The most obvious way is to simulate all the interactions between layers. Although this is straightforward to implement, it might cause higher variance and also it is not possible to find pdf and bsdf values for $(w_i, w_o)$ pairs, obviously. Arbitrarily Layered Micro-Facet Surfaces [WW2007] presents a method that unifies arbitrarily layered microfacet surfaces into a single surface model. However, there are some issues with this paper: When sampling a direction between layers, a direction is chosen according to the individual brdfs of the surfaces. So, if a layer is rough, the transmitted or reflected direction is chosen accordingly. How