Mirror operation : all vertex positions must be reflected by a specific plane (here YZ).
Synonyms: FlipHorizontal, SymmetryX, MirrorX,
What implementations I already know that work:
1) Multiplying by -1 scale. Unfortunately that is not allowed in unity because it messes with physics and lighting.
2) Vertex Manipulation. Yes, it works!!!
And now here comes the "Myth" from mr. evil person...
Mirror operation can be implemented if you get a "lucky" quaternion rotation. He says that:
a) if "euler rotation" suffers from Gimbal Lock, and Quaternion doesnt.
b) Then If quaternion (Matrix 4x4) cannot represent mirror operation, then increasing the #dimensions to Pentaternion (Matrix 5x5), Or Hexaternion (Matrix 6x6) is sure to solve the problem.
Note: I am not looking for "Reverse" operation (15 degree rotation converted to (360-15) degree rotation at that axis). I am looking for a way to "free" my model from those rotation limiting axes... I tried everything but couldn't achieve "Red" projection with a quaternion, maybe I miss something...
Is he right ? Or a quaternion cannot implement reflection and that myth is Busted?
Unity allows me to use all transform operations (Translation, Rotation, Instancing) but not scaling (messes up physics and lighting).