I have to perform dummy insertion after routing to meet desity rule,meanwhile,the layout contains hard blocks which not allow dummy,I have to obstruct dummy for them, kindly you tell me how to obstruct dummy for hard block? By the way,blockage seems prevent net routing not for dummy prevention,isn't it?
We too faced a similar problem. What we did was place a metal over the macro( or the place where you dont want to do the metal fill). After doing the metal fill delete the metal you added before doing density fill. It is kind of work around. I think there will be a better way to do but the above thing worked for us.
Adding OBS for the Macros is smart solution other wise you can go through adding blockages on everymacro
anyway u have to delete obs/blockages added before exportiong gdsii
in former we have to run metallfill with obs in lef and get the metall fill database save it , exit and once agrin we have to load design with actual LEF before exporting gdsii