Hi Jean-Paul - the part that is not so simple with your Network is the sudden 90 degree turn of the section at the end.

You've got several curves approaching that all in similar positions:



Then suddenly the end one is in a much different orientation to the others:



That sudden shift in orientation is going to make that area complicated.

Think of it like Loft (which Network is similar to in several aspects) - just because you have simple flowing curves doesn't necessarily mean that a loft through them is also going to be a simple shape if they have violent sudden changes in orientation between each of the sections...

You might try making the network not quite come all the way to the tip, maybe try to only model up to a 45 degree angle at the end instead of a full 90 degree sudden turn at the end. Then that might be more natural to put in a blend in that area between the 2 halves to complete the shape...

But compression or sudden changes in orientation will tend to apply a lot of constraint pressure on the generated surface in those areas and that tends to make for a type of bunching effect.

- Michael