My conversations turn into code a very high % of the time.  I do not know if the test to flip the sign of the 4th arg negative is right, just a guess.  Should be some multiplier arg to allow normals to be > than 1, in this case?   Recommended method to add to MirrorTexture: /** * Build the mirrorPlane for the texture, based on where the texture is going to be applied * @param {BABYLON.Mesh} intendedMesh - Mesh applying texture (should be a Plane) * @param {numb