[Maya] ~ Rigging, overlapping IK chains seem to be unviable, I need help

Steamy_Steve

Hi everybody.

I'm working on a gargoyle animated character for the game design course I'm following and I've stumbled on a problem with IK chains for the legs.
[WARNING: this is my very first attempt at rigging and animation, vague directions won't help, please provide detailed solutions.]

The green line includes hip, knee and "heel".
The purple line includes knee, "heel" and "ankle".
The two red circles are the controllers.

My goal is to animate the legs in some sort of "pedaling" movement when the gargoyle attacks.
I tried with a single IK chain from the hip to the "ankle", but the result is quite messy because the solver makes the knee rotate in crazy directions.
So I tried with two overlapping IK chains (which is the reason behind the scheme colors distribution in the attached image), but odd things happen and the result is nothing like what I'm trying to achieve.

I'm sure someone else has already faced and solved this type of anatomical configuration and, given enough time, I could as well.
But, as I already stated, this is my VERY first attempt at rigging and animation, thus I lack the knowledge and experience to support my problem solving process.

Please help. -.-'

sprunghunt

Something to keep in mind is that vertebrate animals have the same bone structure. 

https://en.wikipedia.org/wiki/Comparative_anatomy

So what you want to do is rig this like it was a human leg and treat the bottom half as the foot.
In this picture you can see that the wrist on a human hand is the same as the ankle on a dog.

https://en.wikipedia.org/wiki/Comparative_anatomy#/media/File:Homology_vertebrates-en.svg

Alex_J

Yeah, I was going to say, the only difference in most mammals is how long the carpals/metacarpals are, more or less. The bones and muscles are the same and operate the same, but when their proportions change is gives better leverage for different types of movement. 

So, long story short, just make a human rig but change the position of the joints.

Steamy_Steve

@sprunghunt ; @BIGTIMEMASTER ;

So....there's no way to use a single controller to extend/contract the whole leg in one go?
Or to use two controllers to manipulate two overlapping IK chains?

Originally, the second controller would only move the last bone of the leg, from "heel" to "ankle", but then I thought that animating the "pedaling" movement with two controllers set this way would've felt unnatural.

I guess this is the *standard* solution, but aside the accepted/conformed method, would there be a way to manipulate two joints with one single controller? =o

Gonna go with your suggestion, but let me know if you (or anybody else) can answer my question.
Thank you.

Alex_J

That's about the extent of my usefulness here. I only ever worked with humanIK rigs. 

I don't think there is a lot of riggers here, but there is a few. Maybe they can help, but I have a feeling "would there be a way to manipulate two joints with one single controller?" isn't a question that's answer is short enough somebody is going to take the time to answer it step-by-step for free. I could be wrong though. 

That's why it's good to start out with the basic stuff first (not that even "basic" rigging is very easy), so you can build the foundational knowledge to develop more advanced solutions yourself. Because nobody is going to just give away all the details to complex stuff it took them years to develop. People do this for a living, ya know.

sprunghunt

Personally I would just turn the IK off and forward animate the pedaling motion. IK looks better when there's a force on the end of the limbs. For free floating movement often FK is easier to get a realistic motion. 

Steamy_Steve

BIGTIMEMASTER said:

[....] Because nobody is going to just give away all the details to complex stuff it took them years to develop. People do this for a living, ya know.

Which is why I ask this kind of things on a forum rather than professionals' personal sites. x)

Steamy_Steve

sprunghunt said:

Personally I would just turn the IK off and forward animate the pedaling motion. IK looks better when there's a force on the end of the limbs. For free floating movement often FK is easier to get a realistic motion. 

I guess I could agree, at some extent, but as I said I have not enough experience in rigging/animation to fully understand where one method excels over the other and viceversa.
And, to be honest, I'm not planning on becoming an animator myself, I'm just trying to have an exhaustive comprehension of the whole pipeline in videogames development so to be able to pick what fits my talents and skills best.
Which is why I'm following that game design course, it covers the whole process from assets design to in-engine implementation. It has its limits, though, there's not enough time to go truly in-depth, it's like skimming through a book.

kwyjibo

I would make IK (rp solver) chain from hip to heel, then use IK (sc solvers) single bone chains for each section of the foot. Foot is everything from heel down. What you're calling "ankle" is really ball of the foot. Control the foot with a standard reverse foot lock setup. You'll find plenty of info if you google reverse foot lock. As others have pointed out, you can turn of the IK when animating motions where foot is off the ground. 

Steamy_Steve

kwyjibo said:

I would make IK (rp solver) chain from hip to heel, then use IK (sc solvers) single bone chains for each section of the foot. Foot is everything from heel down. What you're calling "ankle" is really ball of the foot. Control the foot with a standard reverse foot lock setup. You'll find plenty of info if you google reverse foot lock. As others have pointed out, you can turn of the IK when animating motions where foot is off the ground. 

I truly appreciate your contribution to my quest for animating a non-standard humanoid model, but you're being too cryptic, with those terms....remember I'm a literal beginner. ^^'

Mark Dygert

I don't want to discourage anyone from learning the fine art of rigging because it is an incredibly valuable skill to have but... Advance Skeleton.

https://www.youtube.com/watch?v=3G9rjbnRNcA

It gets rid of so much friction in the rigging pipeline, and speeds up iteration time. Its a simple workflow that builds high quality rigs, biped, quadruped and birds plus other amalgamations from the systems it uses. The ease that you can test out joint placement and different limb configurations is astoundingly fast and flexible. I can't say enough good things about it. Plus it has a bunch of extra tools for rigging faces, automating lip sync, working with motion capture, creating an Unreal skeleton... it's just awesome.

Steamy_Steve

Mark Dygert said:

I don't want to discourage anyone from learning the fine art of rigging because it is an incredibly valuable skill to have but... Advance Skeleton.
[....]

Argh, automated solutions, my true nemesis!! xD