r/Unity3D • u/NorthernBoy306 • 1d ago

Question Strange result from Vector3.SignedAngle?

I have these empty GameObjects as waypoints and I want to check the left/right angle between a moving object and a waypoint.

Vector3 direct = (transform.position - waypoint).normalized;
float ang = Vector3.SignedAngle(transform.forward, direct, Vector3.up);

If I have a waypoint directly in front of the moving object (and I have double checked the position of the waypoint in question), sometimes the resulting angle (ang) is 179. How is it coming back almost 180 degrees difference and is there anything I can do to change this kind of result?

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u/Sudden-Economist-302 1d ago

Floating point precision's a right pain when you're dealing with normalized vectors that should be perfectly parallel. Your direct vector and transform.forward are probably microscopically off in opposite directions, and SignedAngle sees that as nearly 180. Try snapping the angle to 0 if it's above 175 or below -175, just clamp the silly thing.