Spline/curve aligned handle adjustment

[thoslos]

Here is a post where someone thought their handles were resizing automatically, but it turned out to be an illusion because they were moving a handle not aligned to the view plane, causing the other handle’s changing orientation to make it look longer or shorter. I could definitely see that throwing me off since I work in 2D axis planes the majority of the time.

Original post:

Changing the handles on the two sides of a Bezier curve control point independently

I’m having a problem with Bezier curves using the default aligned handles. When I first create a Bezier curve, I can grab the point at the end of a handle and move it toward or away from the central control point, changing its length, without changing the length of the other handle. Later, something has changed and changing the length of the handle on one side causes a proportional change in the handle on the other side. In other words, initially I can change the length of the handle on one s…

Solution:

Changing the handles on the two sides of a Bezier curve control point independently

I figured it out. What I describe in the OP appears to happen, but not really. It’s an optical illusion. As I might not be the only one caught out by this, a brief explanation may be helpful. In the first image below, you see what appears to be two identical curves that are part of the same object. The second image shows the result of moving the right handle of the right control point of each curve -0.5 Blender units. The result for the top curve is what you would expect, but in the bottom…