Rhino sectioning problem

I made a knuckle point in a surface by compacting 3 control points. But after doing that I can take any section in that surface. How can i solve this problem???(the file and screenshot are attached)

 

I did something like, create a new curve using extract wireframe and created a new surface from curve network. I attached a file with a good surface

 

I have had a few problems with RH4 taking sections, though these seem un-related and have been solved in RH5 (WIP). The better way to create a knuckle is to change the control point weight, rather than putting several control points at the same location.

Hope this is of some help.

Tim B.

 

Thanks a lot Tim B,,,,
Your idea about control point weight to create knuckle point was great.
I attached the modified surface (Rhino File)