# Why does a bezier curve twist when rotated?

If I create a bezier curve and rotate it in edit mode it does not accordingly rotate the tilt of the handles which creates an undesirable twisting along the curve.

Here is an example using a bezier circle with a square used for a bevel object:

Here it is after being rotated 90° about the y-axis:

How do I prevent/fix this?

• Probably is a bug, or the way that this type of transformations is handled, probably... Aug 15 '15 at 14:28

According to Wiki:

A 3D Curve has Control Points that are not located on the Curve’s local XY plane. This gives the Curve a twist which can affect the Curve normals. You can alter how the twist of the Curve is calculated by choosing from Minimum, Tangent and Z-Up options from the drop-down menu.

There are three tilting calculation methods. Choose the one that results as expected.

• Is there any documentation on how the Twist Methods actually work? Having to try them all out is vexing to me.
– Ben
Apr 18 '19 at 6:33

I'm not sure if I understood your question correctly, but I've been going through a problem of tilting Control Points, I tried using R but it didn't work, by researching it, I found out that the right way to rotate a Control Point is by selecting it in Edit Mode, and pressing Ctrl+T.

I used Minimum as a Twisting method, toggling to Tangent didn't do me any good, specially when I used a curve from mesh, using Tangent gave a terrifying results, while this method worked just fine as expected

In addition to Leon Cheung and Georges answers, there are two other ways to adjust the tilt of the curve.

1. In the Properties bar of the 3d view, you can edit the Tilt property for individual control points. The hotkey for this is CTRL+T, as Georges described:

1. In the data properties tab for the Buttons/Properties view, you can also change the interpolation method for the tilt. This is found under the Active Spline section:

A way to "solve this" is to select the "vertex" that is bad (the first), then the previous one (the last), subdivide by 1, move the new vertex where the error vertex is and delete the old vertex, that should fix the "continuity".

You can see in edit mode where the "direction" of the flow is, those little "arrows" says where the curve is going and how it twist (because lines/curves really don't have twist) so it is visually visible.