View Full Version : Are the old z-axis bones still useful for something?

10-15-2008, 12:50 PM
Since the 9.5 version we´re all happy with the new bone type, called joints.
The new rigging videos from Proton are so helpful and great, what leave me a doubt about the old bones type: are they still useful? does it have any advatange over joints? should I use anymore for other purpose other than compatibility?

10-15-2008, 01:09 PM
Yes. If you animate using ONLY bones, the old z-bones offer better rotation control.

Make a 2-bone chain and at the end of the chain, add say, 3 bones in a finger-like attachment (all the same parent).
Now rotate one bone in the finger formation using "Rotation" tool.

Now, try it with joints.

10-18-2008, 12:09 AM
i go with adamred... i still use zbones for all my control rig and animation needs, but i attatch a joint hierarchy to do the deformation (generally just using the "position-same as item" thig to match the joints to the bones at the necessary points), and joints do seem for the most part to do better deformation, though ive still come across the odd sitch where a zbone was a better choice... so its nice to 'ave em both.

jin choung
10-18-2008, 01:06 AM
yikes... this is the kind of thing that i was dreading with the implementation of joints as is.

look at the current joints as what newtek INTENDS to replace zaxis bones with....


BUT... they're not finished with joints yet. it doesn't take rotation yet as mentioned.

this is another classic lw frankenstein version of bolting something new on WITHOUT consolidating and stripping out that which is old.

for the sake of compatibility and INCOMPLETENESS, we have both.

should there come a time when joints is implemented completely, there would be NO REASON to have zaxis bones EXCEPT for compatibility.

in blender, you can have all kinds of different bone draw styles... but it doesn't require having two separate systems.

actually, newtek should take a look at the blender system because it takes into account something that lw will probably have to struggle with - joints that are parented but NOT connected and joints that are parented that ARE connected.

maya only allows the child bones with a visible connection. zaxis allows both without a functional difference.

blender provides both but there IS a difference in functionality.

we should NOT keep zaxis bones around just for the sake of allowing for a non visible connection.


A Mejias
10-21-2008, 05:42 AM
yikes... this is the kind of thing that i was dreading with the implementation of joints as is....

...we should NOT keep zaxis bones around just for the sake of allowing for a non visible connection.


Could you do this with a null as the non visible connection parent for the joint?

jin choung
10-21-2008, 07:45 PM
yup... that proton covered that in one of his videos.

i think that's just about the only real advantage that that null trick does but it works if you need it.

frankly, it would be better if every joint just had an option to not draw the bone connection from the parent joint (or with a ghost bone or something). then all bases would be covered... even though someone who uses it badly would end up with a skeleton in which it's impossible to tell what's connected to what by looking at it.


10-21-2008, 09:29 PM
I dunno, call me old fashioned, but I do like the paradigm of the old z-bones. You place them where you need them, without having to have links between them all. You don't have to have an end joint at the tips of fingers or toes. That's useful for game creators since you can use less per character.

jin choung
10-21-2008, 10:50 PM
but there's no real functional difference though. just cosmetic. maya counts joints not bones... the connection is just a drawing.

but the cosmetic thing does make a difference when you're using bones/joints to rig a face... freakin' pain in the a$s to see radiating spike balls around every head... makes selection and stuff tedious.

lw and messiah are much more manageable visually for rigging a face with bones.

anyway, that's why it was never a problem converting a skinned character to/from maya using polytrans or deep exploration.

again, this is why i was flabberghasted that they decided to ADD joints... wtf for?! alas... anyway, i hope they clean up the mess soon and we get back to a single paradigm again (under joints - and mothball bones in the back of the closet just for the sake of compatibility). i'm getting sooooo tired of pointless redundancy.


10-22-2008, 12:48 AM
But for weighting, you really need to know where the 'bone' is to figure out the influence. Which means you need that end joint. Okay that isn't going to matter much if you're weight painting your mesh all over again, but even when I've painted weights in LW, you don't need to do as much work since a lot of it can be done by the auto weighting.

jin choung
10-22-2008, 12:43 PM
i dunno, i haven't found that lw does a markedly better job in autoweighting than maya does without hold bones and stuff...

actually, blender might have the best implementation. you can just switch modes for using joints or not, there is a functional difference, the hot dog force fields based on the bone are nicely visible with vertex coloring showing the influence on the mesh and after tweaking force field values, you can BAKE it to weights. THAT's a really nice system imo.

oh and blender also has the advanced "heat weighting" methodology that's much better than either maya or lw's autoweighting. http://www.blender.org/development/release-logs/blender-246/skinning/


10-22-2008, 02:22 PM
I didn't mean the algorithm was any better between the apps. Consider a sphere with bones all the way around the outside. If you have the same number of bone/joints in the same place, so the rotations are the same, there's going to be a gap between the last joint and first joint in maya/lw's joints, whereas you can fill that gap with a z axis bone in LW. When you autoweight them, this leads to a discontinuity in the maya/LW joint system (I just tried it, and it's not a smooth fall off) but the Z-axis bones still has a smooth falloff, which is what you're going to get inherently with this type of bone.

jin choung
10-22-2008, 03:28 PM

didn't follow that at all.

you're describing a "snake" of bones that's clinging to the outside of a sphere? and that there's a disconnect or sharp fall off between the head and tail?

why would it be different between zaxis and joints?

and what's the gap that you're talking about? what if you just added a joint so that the last and first joint are coincident?