Extra Limbs, Is it Possible?

In trying to make a new skeleton using all of the same bones, in the same hierarchy that SL uses, I tried to move limbs around a bit, but when I imported the bvh into SL, the skeleton retained its human proportions rather than the ones I'd hoped to achieve. Is there a way to copy over the scale and translations of tho bones, or are the rotations the only thing that copies over?

Thanks, Drake




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Extra Limbs, Is it Possible?

This may be a stupid question, but is it possible to upload an AO that makes use of more body parts than what is already the standard used by SL? What I mean by this, is an avi that had an extra set of arms, or an extra set of legs (like a centaur, for instance). I have a fair deal of experience with the non-Second Life side of 3D work, but I’m fairly new to SL, so I don’t know what’s possible with their system, and what is not. Are you able to create an AO with more bones than the standard avi has, or is this a fixed limit that cannot be played around with?

Any help would be appreciated, thanks.

Well no, and yes. Using SL's animation system you can only animate the standard body parts. You could conceivably have an AO that not only animated the avatar but also controlled prim attachments designed to look and work like prosthetic body parts, so it would be a mixture of avatar animation and prim animation. You can use special animations to hide the default body parts (many very small avatars kind of fold up the body to keep it out of the way), but you can't add to the mesh.

It's not a stupid question in the least. In fact, this is a major point of contention among avatar makers.


Yes, it can been done.

No, at the time of this post, it cannot be done in spec, or in anything other than a hacked viewer, client side.

But it can be faked, in equally hackish ways.


The most popular "faking" technique includes animating certain bones of the default shape in ways that appear "independent" to other bones in the set, then linking to these.

This effect works on many avatars with scripted "wings" or nonstandard appendage counts, but the quality of animation takes a significant hit due to the lack of flexibility.




Another popular method involves prim animation, which branches into several categories.

* You have your keyframed animations (using alpha to create a visual animation).

* You have your scripted movement (not exactly fluid in most cases, and difficult in sets, but plausible).

* You have your blatant abuse of flexiprims (tails, flowing clothes, hair, simple appendages, and some types of wings).

* And sometimes, you have very elaborate combinations of any of the above types.



That should be enough to get you started, anyway.

PS: A little bird tells me that the Lindens *are* interested in suggestions to this end...

Do the body parts have to keep the same connections? Like.. Let's say that in order to gain an extra set of limbs, I could give up the flexibility of my hands and feet (or maybe my ears, eyeballs, and nose), and move those bones elsewhere, but still have the SL names to them.

Unfortunately, yes, these bones have to have the same relative connections. It's what makes faking these animations so hard... =/

So, the easiest thing would probably be to use scripted prims? In the use of scripted prims, can they read the rotations of the set bones?



EDIT:
I just had a thought. If the rotations of bones could be read by a script, and then used to make a prim move accordingly, could two sets of bones like... the ears and eyes be used to control the 'fake bones' that made up the two new limbs? The ears and eyes would still remain where they normally were as far as SL was concerned, but their movements would control prims attached elsewhere on the body. That way, the effect of an AO with extra bones could still be "achieved" without actually adding bones or changing how bones were linked to each other. Also, nothing would be attached to the ears nor eyes, so their movements would have no other effect on the avi other than the extra limbs. Is this a reasonable method, or a shot in the dark using a gun loaded with blanks?

In trying to make a new skeleton using all of the same bones, in the same hierarchy that SL uses, I tried to move limbs around a bit, but when I imported the bvh into SL, the skeleton retained its human proportions rather than the ones I'd hoped to achieve. Is there a way to copy over the scale and translations of tho bones, or are the rotations the only thing that copies over?

Thanks, Drake

Get a multi-limbed avatar, like a dragon or an arachnid, from Grendel's Children or some other avatar maker.

You'll note that these have their own AO/control HUD. Some motions may be automatic, others may be manually controlled by the HUD.