Dear Karthik, 

I don’t think the material is the first issue regarding the choice between local or hammer optimization. The choice of one of the other approach will be prefered regarding the state of your design ( you may refered to the article concerning optimization to figure out your choice )

One major distinction regarding the material between both of these optimization approaches, is that the material substitution can’t be used in local optimization whereas this is possible with hammer optimization. This possibility is very helpfull in a designing process. However I don’t know wherther you could restict the substitution to plastic material is the material choice has not been set in advance. 

I hope it helps.

Have a nice day,

Pascale

Dear Pascale.Parrein,

Thanks for your reply. The choice of material is set to plastic like E480 & OKP4. When running hammer optimization, it shows invalid conic on surface.

Dear Karthik,

I don’ think that the error notification on conic is related either to the material itself nor to the optimization method itself. You should possibly have a look on the sag of the lens. 

Have a nice day, Pascale

Dear Pascale.Parrein,

Thanks for your clarification. 

Have a great day