How to compute the angle between points in the same direction?

[farouk.serragedine]

@J-Rob

I need to compute angles between points or vectors, but the angle does not always occur in the same direction. How in this example, the angle between XA-XB and XA-XC is anticlockwise, but not the XA-XD. For the angle XA-XD I need to have the 200° and not the 160°.
Any advice?

One way to calculate the angles between points or vectors in different directions is to use the dot product and the cross product. The dot product can be used to compute the angle between two vectors, while the cross product can be used to determine the direction of the angle (i.e. clockwise or counterclockwise). Specifically, the cross product of two vectors can be used to compute a third vector that is perpendicular to both of the original vectors. If the resulting vector points in the same direction as the positive z-axis, then the angle between the two original vectors is counterclockwise, otherwise, it’s clockwise.

Another way is to use atan2, which is a variant of the arctangent function, that can determine the angle between two vectors in 2D space. It can distinguish between angles in the range of -180 and 180 degrees.

Check this thread out :

How to get Positive and Negative Degrees (Angle Node)?

The Angle node in RhinoCommon returns the angle between two vectors in radians, and this value is always positive. If you want to get a signed angle in degrees (i.e. an angle that can be positive or negative), you can use the following approach: double signedAngleInDegrees = angleInDegrees * Vector3d.VectorProduct(vec1, vec2).Z; The Vector3d.VectorProduct(vec1, vec2) calculates the vector product of the two vectors, which has the direction of the angle of rotation. The Z component is positive…