I want to rotate a nurbs curve control points. On it there is a plane following de curve. If i tilt the control point for example to 90 degree, it rotates like to 80 degree. And to set it like 90 i have to put it to 140 degree. With bezier curves there’s no problem. I put 90 degree to tilt bezier and it tilts exactly 90,
here the nurbs curves tilt images
trying to 90 degree but looks like 80
This has to do with how nurbs curves work, to convert it to a bezier curve you need at least 6 points.
To change the tilt of a nurbs curve nicely you need to tilt 3 points.
I do not know the mathematical explanation but here I tilted all 3 points 90º to get the middle one at 90º.
In your case select your point and hit “Ctrl +” to expand the selection and then subdivide the curve.
Then select your point (the one with the red circle) and the 2 new adjacent ones and set the tilt of all 3 to 90º.
thank’s that works fine! It’s for making a road. I’m importing the nurbs curbe from rhino thath has specific coordinates. im gonna do only 10 degree camber as maximum, the 90 was for the example.
Also why your plane is so smooth when it twist?. Mine it’s exagerated but looks like polygonal because is a plane that i arrayed around the curve
Because I extruded the curve in its geometry settings, I did not use a plane. If you do this the smoothness will depend on the curve resolution.
I have found that even when you set the 3 points to 90 the tilt in the middle is not quite 90º.
Here in Orthographic view I had to set the middle one to 122º to get 90º.
The tilt seems to be similar to subdivision in that it pulls the surface and calculates a sort of average.
So unfortunately you may have to tweak it a bit and use some sot of guide object to get exactly (at least visually) 10º.
Edit
Ok now I think I understand how it works. Because Nurbs curves do not have handles the control points are pulling the surface and averaging.
So to get the 90º you need 4 points. the outer 2 act like handles of a bezier.
Here I subdivided the section again and then dissolved the mid point (just to prove the concept of min 4 points.) setting all 4 to 90º does give 90º in the middle.
Curve3.blend (123.0 KB)
So to get your 10º exact, do as I said before but subdivide twice then tilt the points! (you do not necessarily have to dissolve the extra point I just did it to prove concept)
Not simple but does make sense 
Did you try to activate shade smooth? Object > shade smooth
solved thx!
okey so it works! unfortunatly i think it’s not gonna work properly to make a road. So i was trying nurbs or bezier. bezier probably looks fine. Also i have the option to do it at rhino, cause i’m used to make things there and for me is easier to create nurbs and curbes. Also a lot of thx for your dedication to this post!
Yes Rhino and Cad handle nurbs modeling a lot better than Blender.
