Flipping GH Planes forever? What is going on and how to fix it?

[DavidRutten]

That’s hypnotic.

[GregArden]

@emilio

Usually, in this case, I would chose a ‘UP’ direction (say a ‘Y’ direction or whatever …), so that he plane be well defined.

I added a method ( to v8 )

ON_Plane::CreateFromNormalYup(
    const ON_3dPoint& origin,
    const ON_3dVector& normal,
    const ON_3dVector& y_up)

I couldn’t add a new constructor because there is already a constructor with that signature.

@RIL

BTW, your transform example would be handled by quaternions very elegantly with one of the suggested methods, this one

• Quaternion. FromToRotation (Vector3d fromDirection, Vector3d toDirection);

The function FromToRotation is not well defined as there are many rotations that produce a unit “toDirection” vector when applied to a unit “fromDirection” vector. So I don’t see how this solves the problem of continuously producing a plane ( i.e. oriented frame) from normal vector. In fact David’s reference explains that this is impossible.