Thanks for your reply Michael, The function curve is not frequently used on modeling.

It's about the history, I make a loft or sweep using some curves, but the history will disapear when I maked a Fillet.
The 3D Parametric Modeling likes a "realtime" and "undisapeared" history, if it is a impracticable project for MOI to Parametric Modeling, I think It could use some other easy solution, just like "rebuild" or "replay", It's mean there is a list that what I have did to the object, and then use the list to rebuild them by other parameters. To do this, maybe every object should have it's "Vertex ID" or "Edge ID", something like not so concise as the MOI now.

I realy like the MOI.