Implementing Flow command

Hello everybody!

I am developing an automatization module and I am going to show you one part of the entire module, that does exactly the same as flow command in Rhino.

My main problem is that when I want to flow multiple curves, the macro runs each time for every curve and this is a serious problem if I have too much of them. I am completely sure that it can be optimised because in rhino when I want to flow multiple curves it is momentary and in my developed VB it runs very slowly.

How could I modify the code (input parameter CrvB) in order to run the macro once like rhino does?

I will really appreciate your help.

Regards, 

Enrique