There is no law of conservation of mass in Odoo manufacturing :)
If your UoM of every product is Kg here then you take care of it while creating products/ BoM. But if you are working through different units and still want to act on "law of conservation of weight" you've got to figure out a customized solution or consult an expert.
Thanks
Vishal
4 years later and I am faced with the same question, maybe it is badly elaborated:
So let's go:
in a product with a BOM and a manufacturing route, can I not obtain the weight and, why not, also the volume automatically?
product C Weight = component A + component B weight
is it so hard to automatically calculate and provide this information in an integrated system?