I'm trying to find out the weight of an piping assembly that I did.  I've assigned materials for each part that is included in the assembly which is necessary in determing the weight.  What I'm not sure of is, if there is a need to assign a material for the pipe and pipe fittings considering that these are already pre-installed in the software.  So, do I need to assign a specific material for the pipe and pipe fittings to be considered in the weight computation (?), OR, no need as it is included automatically in the computation?  'Appreciate your tips and responses.  Thank you.