请高人帮忙解释一下这几个参数分别是干什么用的,有什么区别 c@Q&i  
type : table qEajT"?  
          fresnel ZYo?b"6A  
          stack ]@A}v\wa  
          grating  $
n"*scyI  
         anistropic `Tk	GI0q  
         coating DLL t5;)<N`  
scatter model: Td,s"p>Vq  
         ABg }C!g	 x6  
         Elliptical  ABg /lDei}  
        Elliptical  Gaussian RAB'%CY4  
        Table BSDF :jr`}Z%;y  
         Asymmetric   Table BSDF