Questions regarding weighting/enveloping in XSI

Started by RepComm, November 15, 2013, 12:26:09 PM

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I'd like to dedicated this topic to simple/small questions about weighting/enveloping (animating single objects to multiple bones via vert "weighting").
This is not the place to ask "How do I animate?" or "What is animation?" But rather more learned yet simple questions.
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Here's mine:
Can I weight a vertex to multiple bones for use in SWBFI/II? If so, how many can one handle? And how do I tell which one it's weighted to the most? (Some game engines run dual quaternion skinning, so I know it's possible).

November 15, 2013, 02:21:13 PM #1 Last Edit: November 15, 2013, 02:26:09 PM by tirpider
Technically, the MSH format can handle 4 bones per vertex, each with it's own amount (up to 100%).
[spoiler]The info is stored in the WGHT tag which reserves 32 bytes for each vert's weights.
8 bytes for each vert. (bone ref and weight amount)[/spoiler]

However, the documentation (aniguide.htm) says:
QuoteEnveloping
Most meshes require rigid enveloping meaning only one bone influence for each vertex, (this is mostly for soldiers & vehicles). Otherwise, you could have up to 3 bones influence each vertex but you must define it as "-softskin" in the meshes .option file, (I hope .option files are covered elsewhere). ;)

And the best tutorial I have seen for weighting (in XSI) in general is Minilogoguy's JA/JO videos:
http://jkhub.org/tutorials/article/90-softimagexsi-joja-skeleton-bonestags-and-compiling-guide/
In those videos, he is setting up a Source engine model for JA, but all of it applies to rigging and weighting models for any game.
I believe he uses the Weight Editor panel in the mod tool, which is how you see what the weights per vert are in XSI.

-edit
I've mostly noticed 2 bone weights on the units, but sometimes one with 3 sneaks in.
The mungers seem to default to -softskin, but will complain and do a hardskin and apply 100% to the first weight if they find anything wrong (like bad shadows and other weirdness.)

WGHT.. I guess thats what you could use for weighting via hacking it on with Hex editor.. That sounds like loads of fun :P
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It would be awesome to see a 3 or 4 bone weighted model (specificly around the joints, just for smoother animation..), not sure how useful it could really be, but now the world knows!
It really is to bad we can't have new animation banks in SWBF.. It's such an easy task in ever other engine I've been in..

Anyway, thanks for the explanation Tirps!

For hex editing, sure.
Or you can use the entire format and write an editor, or an importer/exporter (which is just "hex editing" thats been automated to remove human error.) :P