I was just poking for the knowledge of how it worked. I can control the collapse point by "order of picking". 2 are not good, and one produces nearly the same result as sweeping does. I was just inquiring for my better understanding of what was happening. But it is not nessasarily a method I would attempt to construct something.

No need to go any further with it. i thought it was a mechanism I couldnt find in the reference. The reference just said, using network with 3 or 4 curves is a coons patch.