Sorry if this has been discovered before. There is more you can do with this and the 'crease' is made with sorting the three shapes. You can make the crease on the other side (IE upper joint in 'front' by simply changing the shapes order. I just thought there "had" to be a simple way to do this. You can have a whole chain of these joints and the higher ones will not move as you rotate the lower ones. Seems very very stable. The ball joint in the middle can be used other ways but I hope this sparks you guys to 'go with this' and make use of it.
I think this is good to point out, as for many folks it will be all they need.
Unfortunately, for those of us who don't want a crease when the joint bends this won't do at all -- in those cases, Vern's rig is still the best solution.
As far as having NO crease you just have to make a mask (or use the masking in AS but I have not tried that yet)
You place a shape that is all blue (in this case) on top of the top shape to mask it but a tad smaller to allow the black (in this case) edge to still appear. You then bind BOTH upper shapes to the same top bone. One will go above the bottom line 'erasing it' the other provides the line.
Here is a NO CREASE video, file, and pic to show you what I am trying to say.
Some people won't use it because it's really just cutout style rigging. There's no 'flexing' at the joint you'd get with the joint under the regional influence of both bones. A lot of people really like that flexing.
A couple of thoughts...
Aside from killing the IK chain (the forearm bone nolonger moving the upperarm bone), you don't really need that small third bone for this. But some people don't like full IK.
You can add a couple of vector points to the upperarm, just a bit above the joint (one on each side). Since this whole arm is point-bound, you can then increase both bone's regional influence to cover these new points. You may need to select the two bones, select these new points, and do 'Bone>flexibind points'. This will add a bit of automatic 'flex' to your rig.
Yeah, I guess that's what I meant, Wes (the flex you get with bones influence). While it's hard to say that my cartoons look "natural" in any sense of the word, I need that flexation not to look totally cutout.
But folks who like the cutout style will benefit from this.
I've done some experimenting with image "puppets" in AS and this is the technique I've used a few times. The "ball" joint can be great for images if there isn't too much detail that needs to "line up".
For image type puppets this works well when you use a feathered or soft edge transparency on some of the parts so they invisibly blend into the ball joint. That ball joint is great because it can extend the rotation of the joint. One part can cover a lot of the rotation but the ball joint can extend further to cover the joint. With images though, the ball joint has to be a separate layer. I'm not explaining well.
This is good technique. I do however agree that it is too "fixed" for my tastes for vector type joints. I like a little "bulging" and flexing of the joint but that's just me.
Another drawback is where the stroke joins or overlaps at the ball joint. There will be a "nick" or triangular chunk at that spot. Probably not that noticeable but it is there. I suppose HD out put might show this more... or a thicker stroke at higher resolution. That join also is never going to be perfectly smooth. there will always be that slight "bump".
These are nit picks of course. Just my thoughts on it. It is simple AND effective... which for some is important... i always have trouble with the "simple" part when coming up with techniques.
