Question about EdgeSrf component

Hi Fellows,

Now I want to generate some surfaces by using the EdgeSrf component , then I use the SubSrf component to get part of them .My question here is I cant work out how to control the result of the edgesrf ? I mean how to decide which side of the surface is U0 to U1 ? and which is V0 to V1 ? I found it seems that the order of the edge curves do nothing . I am puzzled.

Thanks for help .

alpha