shell line optimization by goat

Hi,

I am a very new user of karamba so the goat. currently I'm working on shell stress line analysis. I'm reproducing the example of "Input surfaces and analyze as a shell" mentioned in the karamba website for practice. I have installed the goat but I don't know how to use the software to optimize for the example. Few examples I have seen some examples goat but found not effective. I want to know how to choose the optimization parameter for the example? do the shell stress line pattern will be changed after optimization? can I use NLopt library algorithms by goat?

thanks