[Closed] Trouble With Basic Material Switching

I’m terrible at Maxscript and have tried to cobble together a script that loops through the current selection and if it finds a material with any refraction value greater than black, it replaces that material with a shell material with the original material as the render material and the baked material as a standard Max material with a 20% opacity.

Here is what I have so far:

(		if selection.count!=undefined do
		(
			MatBank=#()
			indexMat=1
			
			for i in 1 to selection.count where selection[i].material!=undefined do append MatBank selection[i].material
			
			for i=1 to MatBank.count do 
			(
				if (classof (MatBank[i]) ==multiMaterial) then (for j in 1 to MatBank[i].numsubs do 
					(
					if (MatBank[i].materialList[j].refraction.red >0)  then ($.material = Shell_Material originalMaterial:(MatBank[i].materialList[j])
					MatBank[i].materialList[j].viewportMtlIndex = 1
					MatBank[i].materialList[j].bakedMaterial.opacity = 20) else (print "not glass")
					))
					
				else (				
				if (MatBank[i].refraction.red >0)  then (MatBank[i] = Shell_Material originalMaterial:(MatBank[i])
				MatBank[i].viewportMtlIndex = 1
				MatBank[i].bakedMaterial.opacity = 20) else (print "not glass")
				)
			)
		)
	)