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Thread: JOINT question loading sample COLLADA file astroBoy_walk

  1. #1
    Junior Member
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    Nov 2010
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    JOINT question loading sample COLLADA file astroBoy_walk

    Hi everybody (Hi Dr. Nick!),

    I am writing a Java 1.1 compatible COLLADA loader for skeletal animation purposes and I am having a heck of a time understanding the JOINT nodes in the astroBoy_walk.dae file.

    Under:

    <library_visual_scenes>
    <visual_scene>
    <node id="astroBoy_newSkeleton_root">

    Lies the hierarchy of the skeleton (afaik), now this seems pretty straightforward at first, I simply grab the child elements that represent the local bone transformation, and then look for child elements named 'node' and that have type="JOINT".

    Then I noticed that there are elements in this hierarchy that are 'node' elements but have type="NODE". They do not have an sid attribute, so I am ASSuming they don't affect the skin since the skin data holding a name array of joints affecting the skin only holds SIDs.

    Now, these 'node' elements with type="NODE" have child elements that appear to be local bone transforms.

    The first one I run into in the astroBoy_walk.dae file is "astroBoy_newSkeleton_headEnd", and it has no children, so I would presume I could safely ignore it; however, later on in the joint hierarchy I run into a 'non JOINT' node between two 'JOINT' nodes.

    This happens between the node where the id="astroBoy_newSkeleton_L_wrist" with sid="Bone11" and the node where the id="astroBoy_newSkeleton_L_index_01" with sid="Bone16"

    I do not know what I am supposed to do with the node that is in between (node id="astroBoy_newSkeleton_L_indexOrient" with no sid)?

    Am I supposed to store the local bone transform data of this node of type="NODE" for use with something later? Do I ignore it completely?

    If this wasn't reference sample from COLLADA itself, I'd be worried it was some sort of exporter artifact or error.

    Help?

    Thanks,

    WTH

  2. #2
    Senior Member
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    Re: JOINT question loading sample COLLADA file astroBoy_walk

    Treat all nodes equally. There are no exceptions or special cases.

    The type attribute is only a hint to applications that want to visualize skeleton rigs in some fashion.

  3. #3
    Junior Member
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    Nov 2010
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    Re: JOINT question loading sample COLLADA file astroBoy_walk

    Marcus, I VERY much appreciate the reply .

    So, to clarify, it is treated as a part of the skeleton and should be treated as such (therefore accumulating its local bone transformation data), but since it has no SID it won't affect the skin directly - otherwise it is exactly the same (meaning there may be animation data that applies to it.)

    Cheers again,

    WTH

  4. #4
    Senior Member
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    Re: JOINT question loading sample COLLADA file astroBoy_walk

    All the nodes are part of the skeleton transformation hierarchy. Those with sid or id (anachronistic) may also be influences and may be animated.

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