I am looking to attach Data attributes to blocks. I want to tell each block how much volume of liquid is inside of it's pipes (I will be telling each block what it contains so AutoCAD doesn't need to do that calculation) and then I want to be able to extract that information sorted by layer and/or block names. The ideal solution would be if AutoCAD could then calculate the total volume of liquid within a given set of pipes, again designated by layer or block names. How can I do this?