Moho Animation Forum

I'm focused on building a character that speaks to the camera. To help create the forshortening effect I have to Scale as well as Rotate bones.
My character stands in front of a Brooklyn townhouse and I want him to be able to stand in front of and squat on the stoop.
To raise the knees I created smartbones that scale the thigh bones. This works fine if the character is going to sit into a chair but squatting on a stoop means you would be looking at the bottom of the thighs. I want the knees to be slightly above the belt and spaced apart.
My first thought is to create a second set of thigh bones that are horizontal. I could add additional leg layers and use Visibility. I don't know if that makes sense.
This forum is full of brilliant animators and I'm hoping someone can help me solve this problem.

Hmm... took me a while to figure out what you are trying to do but now I see the issue.

Have you tried "negative" scaling of the thigh bone? This would put it up above the belt line. The tricky part is the leg shape. The thigh and calves would need to be separate shapes. Also the transition of the negative bone scale could be little rough. You could use the smart bone controlling the "squat" action to also adjust points.

You could use two different leg layers with visibility, but I would probably use a switch (with nested bones enabled for parent layer). You could then use the smart bone to "switch" the layers. I think that both of these layers would probably be exactly the same so you may not need a switch and just change shape colors or points on one single layer. The "change" would possibly be some point movement or shape color change (when squatting the visible backs of the thighs would be darker). The only issue might be shape or layer ordering. If the thighs "layer" or "shape" are always behind the calves shape then one layer would work fine and make all changes in the smart bone.

If you have a single "squatting" smart bone for both legs simultaneously, then at the half way point of the smart bone action, swap the switch or change the colors of a single layer. At that point you are now in the "squatting" position. Points may not be where you want them, but you can easily move the points in the smart bone action to make it look correct.

Sounds a bit complicated.... just tapping into my stream of consciousness... brainstorming.

heyvern, thanks for your help. I really like the idea of nested bones in a switch layer.
Getting my character to stand and squat in a front view is tougher than a head turn, in my opinion. A head turn left and right with a phoneme switch only required one bone. Smartbones are truly amazing.
What I want from the legs and, eventually, the arms means I need bones that both Scale as well as Rotate. Nested bones in a switch layer sounds like a great idea. I had never heard of that.

is this the sort of thing?
It's extremely crude, i spent no time on it, but you get the idea.

The back thigh doesn't NEED to 'rotate' the top is the bottom when the knee is up - i could have added more points and shaped the thigh and tinted it so it can show below the calf, but you get the idea hopefully...

I just shrunk the thigh bone till it was small, then translated the shin bone up. This is all in 1 bone to control both legs, but you could have them independent.



file: http://www.mediafire.com/?q85ploqy47sya7f

funksmaname, seeing your example helped my thought process. I thought to myself "Why didn't I think of that before?" I'm embarrassed but it's better than being stuck. Wow...I made the thigh/hip into a single shape, one for the left side and another for the right side. I'll redraw the hips as a separate shape and add two more bones. I don't know if that's what you intended but it was effective. Thanks.
Smartbones simplify rigging. I guess I got spoiled.

It is definitely taking time to adjust to the fact things can be much simpler now

Instead of thinking of complex ways to bend, shrink and rotate bones or groups of bones you can literally do finely articulated point motion and just assign it to a bone that's not even bound to anything... ofcourse this was always possible, but not so easily repeatable, and previously not mixable - smart bones marry the control of point motion with the flexibility of bone control. It used to be a trade-off but now you potentially get the best of both worlds...

p.s. nothing to be embarrassed about! sometimes it's hard to see the wood for the trees.

While trying to figure out how I would build the arms I stumbled upon the idea to put a parented bone inside the upper arm only. That, for me, is a radical thought. For the forearm I'll use point motion and smartbone levers. Same method used for head turns.
I spent several hours scribbling down what I've learned from this thread trying to make sense of it. For example I'd never thought about negative bone scaling. You build a system of doing things and then you have to learn to think differently. That takes work.
I could not make such big leaps in knowledge without this forum. I appreciate this community.

The problem with animating between positive and negative scaling, is as you go through '0' you get a flat result...
To have no bone in the lower arm doesn't seem sensible in theory, but then you may have stumbled on something that might change all our ways of thinking Even if your solution isn't perfect, it might plant a seed to let our brains fill in the gaps and work together to come up with something interesting... If you have any luck with your experimental rigging, please post your results!

funksmaname, The arms are a bigger challenge than the legs. Honestly, learning to do a head turn was a bit easier. I think I'll have to use a number of techniques to get the arms to do want I want. The good thing is I haven't run out of ideas yet.
I should mention that in one of your tutorials you talked about Onion Skins. My reaction was "Aha!" They helped me solve a big problem I had with the legs. I've learned a lot from your tutorials. I've watched quite a few of them. Thanks for all the work you do.

This is a look at my progress. So far it looks like scaling is best done with SB levers and not by 'skeleton' bones.
(I still don't know how to embed a video. Somebody please tell me how.)
http://youtu.be/zBa-jacp5UY

The whole thread is very interesting, and your example looks just fine.
I`ll give it a go and see what would come out ,)

About the YT links...

Either type this (insert the link between brackets, where x is now) ... or simply go for the large button "POST REPLY", which would open the complete editor, and at the top of the writing box - at the far right - you`ll see youtube button. This would insert the brackets but you`ll still have to input your link in between.

* EDIT *
Bare in mind that you don`t have to input the whole link (like http://ww.....) , just the video ID which is at the end of the link, after /watch?v=
i.e.
http://www.youtube.com/watch?v=l-7IV2qryiQ <----- just this bolded part.

Maestral, thanks. I'll use the [Youtube] brackets the next time I post a video. I'm going to test simple shapes where the hands will be next.