add a meshgenerator to generate new boundary (sideset) from current boundary

[lyyc199586]

Discussed in #24350

^{Originally posted by lyyc199586 May 13, 2023}
Hi all,

I am trying to find a way to generate a new boundary from an existing boundary. To be specific, I want to 'cut' part of the exist boundary:

Reason

It's a common scenario when we need to 'cut' part of an existing boundary as a new boundary. BoundingBoxNodeSetGenerator is not suitable when the boundary is inclined, ParsedGenerateSidset cannot help me with an existing boundary.

Design

Use the old boundary and an expression (say, x>3,2) to intersect and generate a new boundary.

Impact

try to add a new meshgenerator named something like ParsedSelectSideset