I have an assembly that I have imported (stl file) and after assigning the material properties to all the parts I am getting a crazy high weight.  So to get to the bottom of this I wanted to make a bill of materials table to display the mass of each part so I can chase down the offending parts, but when I go to do that I find that all the parts don't have the properties set to display mass and the only way I have found to add mass to that list is to go into each part individually and add the property manually.  There must be a way to change this particular setting in bulk... Right?

If there is a better way to chase down strange weighted parts than what I am thinking, I would love to hear it.  But I will still need to add the mass to all the parts for my final BOM.

Any help would be very appreciated.

Edit:  I am aware of this post about "Edit a Parts Custom Properties from an Assembly File", but I couldn't figure out how to do what it was telling me to do.

Edit 2:  The Correct answer shown here addresses me seeing the masses of all the parts issue.  The answer for how to adjust the properties en mass I believe is below (as of this post I have not gotten it to work quite yet).