Angle from two lines

Grasshopper
1

Hey guys sorry I’m a grasshopper noob but I can’t figure out why the angles are wrong between grasshopper and rhino…

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2

Are the lines planar (to the XY plane ?). If not, GH is measuring the “true” angle in 3D space. it doesn’t care about the Plane, unless you project the lines to a plane and meaure the projected lines.

Just a thought. You didn’t provide a file so one can only guess.

// Rolf

3

Hey I figured it out that GH is calculating the first line like it is the ground plane scaling off into infinity.

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Green is how GH sees the angle…

Kind of confusing i need to a subtraction node to get the right numbers…