 # Curve Frame Orientation

Hi All,

I am making a simple exercise with curves and I want to retrieve the normal vector at each parameter t.

I don’t understand why two of the frames are not planar with the curve.
If i rebuild the curve (with the same degree and points number), all the frames are then planar, but some are flipped!..

Where am I wrong?

curve-frame.gh (6.4 KB)

Giaco

I can’t exactly tell you, why the planes are rotated. My guess would be that this has to do with curvature.
However, you could construct them correctly yourself and get the normal vectors of the curve even before, or without the planes.

Here’s how to do that:

curve-frame.gh (9.0 KB)

1 Like

That component uses the local plane of the curve, which only exists if there’s some curvature. The bits where your plane goes horizontal must be fully linear.

Thanks @p1r4t3b0y for the example.

Your solution is good. Using the Normal to the plane of the surface ( which is the same for any point of the curve), you got the third vector using the Cross Product.

I still don’t understand which is the scope of the Curve Frame Component, if it doesn’t output a series of plane oriented in the same way…

Thanks, in your example, if you don’t want to generate a surface, you could also just manually provide an x, y or z directional vector instead.

Like @DavidRutten explained above, the component uses the local plane of the curve, which only exists if there is some curvature. Both frames that point outside in your example above are on linear piece of the curve, which probably have no curvature.