How do I output the siblings position number? This question is related to this thread.

{% for sibling in entry.getSiblings() %}  
{{ sibling.title }} {{ sibling.orderNumber }}
{% endfor %}


I thought you could pick this out of the ElementCriteriaModel, but that doesn't seem to be possible/available. Twig's for loop won't work either.

The result I am looking for is to echo the order number of the siblings in a structure. 

Parent
Child order number 1
Child order number 2
Child order number 3
Building upon the answer I posted to this question How to get the order number of the current entry in a structure, you should be able to get the order number in your for-loop like so:

{% set parent = entry.getParent() %}
{% set childrenIds = parent.getChildren().ids() %}

{% for sibling in entry.getSiblings() %}
    {% set orderNumber = craft.entries({
        id: siblingsIds,
        order: 'lft desc',
        positionedBefore: sibling,
    }).total() + 1 %}

    {{ sibling.title }} ({{ orderNumber }})
{% endfor %}