Methods to make 3d model of real life curved objects?

Hi,I am a computer engineer, got no background or formal education on solid modeling.All I know about 3d modeling is from making 3d games and modeling 3d models for those.I am struggling when it comes to making copies of complex curvy objects in 3d digitally.How can I find tutorials on this? For example, If I want to make 3d model of a curved lens of sunglasses.What tools and steps experts follow? Are there certain tools for angle or curve measurement they use? http://ift.tt/2fhy5Mi