Where is the line between plagiarism and influence of another artist

[iside]

Good evening !

Got an interesting artist \\\\ sculptor in years already , interesting work , but ... it's all someone else's work. And he had periods , then an artist, a sculptor, is yet another artist . So many went through . Some work directly copy , he said that only " inspired ", but seen as a strong inspiration was what came out the same way. >

I wonder where the line between copying ( plagiarism) style of one artist ( a sculptor, an installer ) and the influence that was exerted on one another. It's very interesting to hear how every man for himself opredyalyaet this time. If possible with examples.

Thanks in advance .

PS By the way , Richard Pettibone no one is accusing of plagiarism , on the contrary show suit and actively sold. An interesting phenomenon , if someone can explain why.