function determineSide( diceTransform )
{
    var upThreshold = 0.99;
    var dotFwd = diceTransform.forward.dot( vec3.up() );
    if (dotFwd >= upThreshold) return 6;
    if (dotFwd <= -(upThreshold)) return 1;

    var dotRight = diceTransform.right.dot( vec3.up() );
    if (dotRight >= upThreshold) return 5;
    if (dotRight <= -(upThreshold)) return 2;

    var dotUp = diceTransform.up.dot( vec3.up() );
    if (dotUp >= upThreshold) return 4;
    if (dotUp <= -(upThreshold)) return 3;

    return 0;
}