@AsurosNsfw It works like this: One should select important vertices which define Penerator shape.
On a Receiver side one should select vertices which would form a closed loop.
@GrumpyOldGoblin @AsurosNsfw It should be selected directly because UE changes indices (I guess during import event). Vertices selection/tracking is done on CPU. For that I wrote C++ code which replicates skinning work. Rest work done in blueprints. It creates splines automatically.
This thread has a breakdown of a simplified version of the fake fluid effect. Here it is just drawing a fluid profile (need to add a bumpboffset to actually draw the fluid surface cheaply next).