//Save to ZBrush 2021\ZStartup\Macros\Misc\ folder and press Macro>Reload All Macros

[IButton,???,"Assign transparent texture to hidden points",	
	[If,[IExists,Tool:Visibility:Grow],
		[VarSet,tmpRgb,[IGet,Draw:RGB]]
		[VarSet,tmpCol,[IGet,Color:Main Color]]
		[If,[IsEnabled,Tool:UV Map:Delete UV],
			[If,[IsEnabled,Tool:Visibility:Grow],
				[IPress,Tool:Masking:MaskAll]
				[IPress,Tool:Visibility:ShowPt]
				[IColorSet,0,0,0]
				[IPress,Draw:RGB]
				[ISet,Draw:RGB Intensity,100]
				[IPress,Color:FillObject]
				[IPress,Tool:Masking:Inverse]
				[IColorSet,255,255,255]
				[IPress,Color:FillObject]
				[IPress,Tool:Masking:Clear]
				[IPress,Tool:Texture Map:New from Polypaint]
				[ISet,Tool:Texture Map:Transparent,[IGetMax,Tool:Texture Map:Transparent]]				
				[IPress,Color:FillObject]
				[ISet,Draw:RGB,#tmpRgb]
				[ISet,Color:Main Color,#tmpCol]
				,
				[Note,"Model must be partially hidden",,3]
			]
			,
			[Note,"Model must have UVs assigned",,3]
		]
	]
]//end of macro