nominalFace

Provides a hint to renderer about the facing of this quad. Not required,but if provided can shortcut some geometric analysis if the quad is parallel to a block face.Should be the expected value of lightFace. Value will be confirmedand if invalid the correct light face will be calculated.

Null by default, and set automatically by cullFace.

Models may also find this useful as the face for texture UV locking and rotation semantics.

Note: This value is not persisted independently when the quad is encoded.When reading encoded quads, this value will always be the same as lightFace.