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■Q2:How to get these three red isolines from green surfaces?
The command under the"Style/curve from surface" only can extract isoline from a single surface, just a partial segment. Even if I extract isolines face by face, the joints of partial segments must be out of alignment
The domain for the isoline creation tool is a single surface. The tool calculates a parameterization based on this domain to create the curve and this is why you cannot create the lines crossing surfaces as you have illustrated in your picture using a single feature.
There is an enhancement in Creo 9 that may support the creations of s set of lines that represent your picture, but this is not something I have tested yet.
In Creo Parametric 9.0, users can now create an isolines curve on a given surface with its location defined by a reference. If you have a common reference for isolines on surfaces that share an edge, then in theory you could align them where they meet the common edge.