Deep Knee Bend (Simple Rig / Joint Compensation Question)

[steamthunk]

Did something change in LW9.6 wrt z-axis bones / joint compensation? I seem to get much more "collapsing" of joints then in past versions. I don't ever remember having to use so much joint compensation previously.

Look at the very simple leg. Ignore the craziness at the hips. I'm still constructing. Tweaked the knee for about 5 minutes and this was the best I could get (see bones properties settings). Anyone else feel that bone deformations use to work better out of the box?

----
Rant space:

In general, I've gone through the LW9 Essentials book and have been going through the Jonny Gordon books to try and gain insight into the entire rigging process. Also watching Proton's videos. Some good stuff in all the sources.

I don't animate so I don't need the perfect rig and am content to do touch ups in modeler or in post, but I've found myself just battling my old rig constantly. So much so that I sat down today to clean slate rig. However, if I can't get a good simple knee bend going I have to stop and ask if there's something fundamentally wrong about my approach.

From everything I've read and heard the ultra fine grain weight mapping is not the way to go. I swear the time I spent on pose/rig issues I could have just modeled the pose in a shorter time.

Sorry for the grumpiness, but I'm just getting really frustrated. 8/

[Dodgy]

I very rarely bother with weight maps now. The way I do the knee is to have a little bone within the knee, so you can achieve deep bends. With joint comp on, this looks pretty good.

[SplineGod]

I also dont use much weight maps. The nice thing about using hold bones as Dodgy suggested is that they can be animated. Heres some examples:
http://www.vfxcast.com/media/326/Simple_Muscle_Bones_pt1/
http://www.vfxcast.com/media/335/Simple_Muscle_Bones_pt2/

I would also add in some corrective morphs which you can create in modeler or layout
nad use something like expressions, cycler, jointmorph etc to tie them to the rotation of a bone.
http://www.vfxcast.com/media/343/Point_Level_Control_in_Layout/

[steamthunk]

Thanks guys that's useful stuff. I increasingly realize that there's a fundamental flaw in a lot of the tutorials I've worked through - the assumption that having a connected set of bones that mimic a real life skeleton is the way to go. Maybe for quick demos that works, but I've had a lot of trouble with finer deformations.

I also maybe just have to accept that it's frakin tedious. Even though Splinegod makes it look easy that's still a lot of work to bend an arm. :bangwall:

[SplineGod]

Theres nothing wrong with having a skeleton that mimics a real one in general. The trick is to know how to correct for bad deformations or add what is needed to get proper or desired deformations.
Each of the things weve suggested can be taken to a whole 'nuther level. There are still other tricks besides the basic ones mentioned. Rigging some of this might seem tedious but once the joint for example works when bent once it will continue to work for eery time its bent, This way you only have to really set it up once.
With LW9.6 theres even more options built into the bones/joints as well as node based deformations that allow even finer control.

Rigging really has 2 aspectsL
Rigging for animation
Rigging for deformation

Ive found that its faster/better to deal with those separately.

[erikals]

I very rarely bother with weight maps now. The way I do the knee is to have a little bone within the knee, so you can achieve deep bends. With joint comp on, this looks pretty good. http://www.newtek.com/forums/attachment.php?attachmentid=78001&stc=1&thumb=1&d=1254617224

..i tried that some time back, but i just didn't understand how to rig it.
isn't it difficult to rig? hyaving that bone in between? or is there some trick to it?

..if there is some easy way around that i'd love to hear about how one can go about it :)

[steamthunk]

Q: Would people recommend joints over z-axis bones? I've only really used the latter, but my minor trials with joints yesterday seemed to indicate they are better behaved with IKB. Or am I just fooling myself? :) There doesn't seem to be much conversation about joints after searching through the forums.

Anyway, I spent a good amount of time play rigging small parts just to fiddle with how things worked more. I stand corrected slightly. I noticed that placing bones in a manner similar to real life does help a bit. For instance, I moved the shin bone close to the front of the leg and I think it works better. I'm used to just burying the bones in the middle of arm or leg. Likewise the elbow a bone much closer to the surface of the skin than something buried in the middle of the arm.

Also, the yesterday was the first time I did bone work in layout. I've always been a skelegon guy, but I have to say this isn't bad. I like the more immediate feel of using my rig (carefully) as I build. Although I've never really have been one to complain about the modeler/layout schism, I'm starting to understand why some are bothered by the break. Here's to CORE getting it all done well.

[Castius]

Technical there is no difference between using joint and zbones with IK Booster. All IK Booster looks at it the transform information.

[RebelHill]

..i tried that some time back, but i just didn't understand how to rig it.
isn't it difficult to rig? hyaving that bone in between? or is there some trick to it?

..if there is some easy way around that i'd love to hear about how one can go about it :)

Its easy enough to rig... its a pain to animate with however, having to work with 2 bones for a single joint, youch... The best way to do it is as a secondary deform structure of bones/joints laid over the control skeleton... And u got all the know how on this my friend... vids 20c-20f on skinning (;

Steam... No, theres no difference at all between bones and joints when it comes to IK, IKB, or any other method of control.... their only real difference is how they work for deforming meshes. As for placing bones in the correct places... remember the important point is not to have the bone in the correct place, but the joins between them... The shin bone is towards the front of the lower leg... but the ankle and knee joints arent, or at least, not so far forward.

Generally I separate out my controlers from my deformers... I use Zaxis bones as my control setup (though I could just as easily use nulls, or lights, or anything else), and I target the result of this skeleton with a joint setup to handle the deformation... Its pretty simple and straighforward tos etup, and gives, so far as Ive ever found, the best control over deofrms you can get.

[erikals]

ah, i didn't notice that part :)
hard to remember everything trying to be a "multi-artist" :0

thanks, i will have a closer look at the videos... :)

[ericsmith]

Its easy enough to rig... its a pain to animate with however, having to work with 2 bones for a single joint, youch...

I do this kind of setup with my Maestro rig, and it's totally transperent. I set the pitch of both the knee and shin bone to IK, and then set up a limit on the shin bone so that once you bend far enough, the knee takes all the rotation. There's no snapping from the limit like you might experience in other situtations because the two bones are basically working together.

Eric

[erikals]

eric, since i have you here... :)

does it come with rigged examples, like biped quadruped?
RigFeaturesv2.3, this one shows the tiny knee bone setup, does it come with that rig?

once the hand is "in place" like shown in the "Hand Pinning" video, is it easy to undo?

[ericsmith]

does it come with rigged examples, like biped quadruped?


Yes. We include a somewhat low poly generic male, female and dog, and Proton's Ninja is also included, all with bones in place ready to run through the rigger.

RigFeaturesv2.3, this one shows the tiny knee bone setup, does it come with that rig?


Yes.

once the hand is "in place" like shown in the "Hand Pinning" video, is it easy to undo?

All you have to do is select the baked keyframes in the timeline and delete them. Very easy to do.

Eric

[erikals]

sounds good :) very good :)

[RebelHill]

I do this kind of setup with my Maestro rig, and it's totally transperent. I set the pitch of both the knee and shin bone to IK

Of course, use as many bones as u like with IK... but this kind of 2 bone setup on a FK joint is a real pain, for the handling of graphs, or even worse the cross rotation of axis (parent>child) when using it not at a knee or elbow, but a shoulder hip, or other... Thats why I prefer to separate out these deform portions from the actual control rig.

[Castius]

I agree with Rebelhill I separate the deformation from the animation rig as much as possible. The fact is a single point of rotation is barely enough to represent something as complex as a knee. In fact a knee doesn't just rotate is slides around and twists. So when you move the pivot point forward to fix one type of deformation you're effectively tying your rig animation to that one type of deformation. So the best thing to do is to put the animation pivot as close to the center of all the deformation you need. Then handle any complex deformation on top of it. For the knee add a knee cap hold bone. Then some tendon/muscle bones that are rigged on top of your animation and use then as extra information to drive your deformation.

Doing this will also speed up your animation rigs. And if you do it right. It also means you can even have different animation rigs for specific needs. without redoing anything on the deformation rig.

[erikals]

...so you mean just a small bone on top of the other 2 bones instead?
(placed on top of the knee)?

[steamthunk]

This is quite interesting, but more pictures would be nice! :stumped: I'm having trouble following if the "deformation" rig is actually a separate rig or is it just more hold bones on one rig. I imagine it to be the latter somehow.

[Castius]

Here is an old script for dealing with this.
http://www.steelronin.com/plugins.htm#RigDeformer
Video:
http://www.steelronin.com/plugins/mov/SR_skelgon_06_640.html

I would probable do it different in 9.6 now. But in this case there is an animation rig and i simply parent the deform bones to the animation rig. I can add or delete as much as i like. Until the deformation is what i need.

[erikals]

yes, that was the word i was looking for... "hold bones" ;)