I have an error in the Surface from network of curves section

Can anyone please guide me to fix this error
thank u

network surface.3dm (4.9 MB)
when i cap this

Hi @thaibui
NetworkSrfwill make a single NUBS surface with no kinks in it, so you need to either round the corners of the top “inflated square” or divide the body up into more parts - see attached.

network surface_JN.3dm (1.6 MB)

HTH, Jakob

thank you @Normand
Unfortunately I can’t view the file you sent and I use version 5

Hi @thaibui
When you’re using a version other than the current (which is V8), it might be a good idea to mention it on the post - quite a lot has happened since 2012, when V5 came out. But here’s the file in V5 format:
network surface_JN_V5.3dm (1.6 MB)