public void AddTo(IMeshBuilder <TMaterial> meshBuilder, Matrix4x4 xform)
{
var x = Vector3.UnitX * _Size.X * 0.5f;
var y = Vector3.UnitY * _Size.Y * 0.5f;
var z = Vector3.UnitZ * _Size.Z * 0.5f;
_AddCubeFace(meshBuilder.UsePrimitive(_Right), x, y, z, xform);
_AddCubeFace(meshBuilder.UsePrimitive(_Left), -x, z, y, xform);
_AddCubeFace(meshBuilder.UsePrimitive(_Top), y, z, x, xform);
_AddCubeFace(meshBuilder.UsePrimitive(_Bottom), -y, x, z, xform);
_AddCubeFace(meshBuilder.UsePrimitive(_Front), z, x, y, xform);
_AddCubeFace(meshBuilder.UsePrimitive(_Back), -z, y, x, xform);
}