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mathvectorprojection

return local 2D coords of a 3D point on a 2D plane in space?

As the title suggests, I don't know where to start on this problem: I have a a 2D plane defined by it's origin point in global coordinates(x,y,z) and its axis endpoints as well, but I don't know how to return the local coordinates of a point on the plane

I found this solution but it gave false results:

// given information

`Vector3 origin;

Vector3 planeXDir;

Vector3 planeYDir;

Vector3 pointOnPlane;

Vector3 v = pointOnPlane - origin;

Vector2 positionInPlane = new Vector2(Vector3.Dot(planeXDir, v), Vector3.Dot(planeYDir, v));`

I don't know where I went wrong, maybe a misconception of planeXDir and planeYDir? I'd be happy if someone could explain or give me an easier solution to implement.

Solution

  • That code is correct, so there're misconceptions or mistakes somewhere. Check that planeXDir & planeDir are orthogonal, and unit (or if not unit that you really want a scaling difference between unit lengths in 3D vs the plane).