NURBS curves are wierd. How to make them works?

[SoundDifferent]

Here’s a default nurbs path:

It containts 5 points by default. Here what would happen if i move some of them:

Pretty much the expected results of some smooth arc curve defined by points. I can also dissolve/delete some points and get an expected results as well:

But lets delete all the points except first and the last one:

And subdivide those curve once to get a point in the middle and try to move it:

And that results are complitely unexpected. Why it doesnt form an smooth arc curve now?

[stray]

It has to do with Active Spline > “Order U” parameter (“…higher value makes each point influence a greater area…”) being capped at maximum point count in a spline. By default it’s set to 5. If your curve only has 3 points, the parameter can’t be more than 3. If it only has 2 points, then it can’t be more than 2…
But as you add points again, it doesn’t automatically raise the value.

[SoundDifferent]

Oh, the active spline section which i didnt even check. Thanks!