select cells behind/within a drawing object

[mgolay]

Hi all; new user here. wondering if anyone can help with a doozy of a problem.
I'm trying to use a drawing object to select a range of cells. and/or values within these cells.

much more valuable if an irregular (polygon) shape can be utilized.
For example; I have a table, and chemical concentrations in each box of the table (representing a surface); each cell has a specific concentration of a chemical (or temperature, etc.). If i placed an image of ...say a hand print on top of it; what is the total amount of chemical they are exposed to (obviously not the entire surface; only their points of contact).

so, if i have a large table with values in all the cells, and I draw a star on top of it (for example); the drawing object would choose (function; in my case; "sum") the values of the cells behind the star.
Of course, with diagonal lines; you'd have to be able to consider:
1) if the drawing object touches the cell; does it include the value
2) if the drawing object intersects the cell; include the value only if more than 1/2 of the cell's area is contained within the drawn object.

any ideas / possibilities?

thanks!

 

[mgolay]

for example...