Reverse Foot IK rig


(Lancer) #1

Just a leg.

This IK foot rig is capable of heel roll & ankle pivot, toe roll & toe pivot, ball roll & toe wiggle… pretty much everything needed for smooth walk cycles. Based on what I’ve been taught in Maya, now transferring that info to Blender while I relearn rigging from scratch.

Attachments

reverse_foot_10.blend (59.2 KB)


(thelowlander) #2

thanks mate, I’ll look into it. I love to check out these new rig sytems that pop up now and then.


(nirmaldavid) #3

Just checked it out…
works absolutely fine…
now if only u would do a quick tutorial :stuck_out_tongue:


(Lancer) #4

Hey thanks both for the positives! :cool:

I know exactly what you mean regarding tutorials. I looked a long time and found some interesting IK rigs; most either missing an essential movement or so complicated I doubt I’d be able to end up wiht the same rig if I tried.

So yeah, I fully intend to make a tutorial for you. I like Open Source; who want’s everything secret?

In the meantime, here are two of the best tutorials I saw which inspired my own design…

http://yogyog.org/texts/legrig/
This simple rig is very close to my own design. The main difference is that this one can’t to the “toe roll & pivot” which is a box at the front of my rig’s toes that can be rotated to make tip-toe movements (up / down) or snubbing out a cigarette (sideways). This is important to me as it allows more precission in allowind the foot to peel off the floor with absolutely no slide. Because mine is made in a later version of Blender, I was also able to incorporate the newer “pole vector” target to the IK knee (that floating K which the knee always points to).
…other than that, a great rig and the basic principle of how mine works.

http://calvin.sdlfk.org/calvin/footTut/
This one, was the one that lead me to the above one. It’s a great study also. For my purposes, I thought it was a tad too complicated, using more bones than I thought were needed for the foot roll… perhaps Calvin is aiming for a bit more accuracy somewhere and I’ve missed the point? Or it could be that the older versions of Blender required more rigging (e.g. the new pole vector target IK solver introduced in 2.47). All the same, while Calvin’s rig toes have toe wiggle (lift toes up) it again lacks the toe roll & pivot.
…and having graduated in Animation (with Maya) from MDS, I’m pretty fussy in insisting that my IK rigs must have toe roll.

So; until I get the chance to make a proper tutorial, you could look at the other ones (I decided they were among the best of the ones I found). In the meantime, if you do know how to pull a rig together (e.g. you can also get an IK solver working), here’s a rough image of how my rig actually works…

http://img79.imageshack.us/img79/2493/iksecretssc4.jpg

When weight painting the foot, only paint the foot mesh to the toe wiggle and the ball roll. The others (toe roll and the main heel control) are merely drivers to the toe wiggle and ball roll bones.

Note that I repositioned the bones for you here to make things look more obvious. The toe wiggle & toe roll bones fall on top of each other, the main base foot actually is in line with the sole of the foot (pulled down for the image) and the ankle would normally look joined on (broken to make the IK solver in the knee work)

The basis for this rig is known as a “reverse foot” because the bones go backwards (up from the toes) to allow for movements like the toe roll & pivot.

Hope this helps you. Might get a proper tutorial up when I have the time.


(nirmaldavid) #5

Hi…
yup… i am familiar with foot rigging in Maya etc…
but am always on the look out for foot rigs in Blender to see how people approach it…
Im attaching my version…seems the same except for the toe pivot that u have that moves the entire foot…
one thing here tho is that i have the feet bones stay with the calf and the thing bone so it doesn’t stretch…even though that might be desirable in some cases…:stuck_out_tongue:

Attachments

ikLegRollTry5.blend (260 KB)


(almux) #6

Splendid! Thanks for the links! And… i’m also looking forward for a nice step by step tut… I never came to succeed with those i’ve seen till now… (But there are many things my brain misses…) ;o


(Lancer) #7

That’s pretty cool how you attached them. I’ll have to study this rig… looks like you’ve got a couple of hammers in there… interesting.

For me the toe roll & pivot was pretty key… and almost every Blender rig missed it. Having a toe roll means the character can peel their foot very easily when stepping off the ground. Just start with a ball roll, then a toe roll and you’re ready for the lift into passing position: no difficult slide or odd angle of lift.

EDIT: Thanks almux… you mean the diagram made things clear?


(nirmaldavid) #8

Hey…
Yup!!! Agree with you a hundred percent…thats how we do it at work mostly…
Hmmmm…I’l try and integrate that into my foot rig…:yes:.

P.S:I know this makes me sound like a doofus…but …what are hammers in this context???a way of saying “some good things in there” or some kind of technical term in rigging :p…sounds interesting either ways.


(Lancer) #9

hammers: more of an observational “looks like” description of how the green arrow (Bone.007) appears when you take off “shapes”… it kind of swings around until it hits the heel, just like a hammer. Just me trying to make sense of what’s in front of me.

I’m really glad I’m starting to get this stuff working in Blender. Been reluctant to pirate Maya so nothing much done since my student reel.


(nirmaldavid) #10

Oh…got that :slight_smile: …I was beginning to think its some tech term im not familiar with…
:D.
…hmmmmmmm…:confused: in fact I dint notice that before…
looks like some pivot thing…maybe i should try some kind of limit rotation max and min to avoid it…???
looks like bone.007 starts getting weird…beyond from Rx -5 and Rx 95.
is that the issue ure talking about…???
I animated in Maya for around 5 yrs and then started blender…was crazy tough in the beginning but i wont look back now…its grown into an artist friendly enpowering tool…
and a wonderful user base that will reach out to help faster than u can get up and get yourself a coffee :).


(Lancer) #11

I wasn’t picking any issues… was describing what I could see… still haven’t fully figured out how it works internally, and I’d like to give it some time to nut out for my own education.

I managed to torrent the “Mancandy FAQ” DVD today… total goldmine in other areas of the body I haven’t really looked at! :smiley:

Hey, apparently the next BlenderArt magazine is wanting to focus next issue on rigging… perhaps that would be a good place to submit short tutorials?


(nirmaldavid) #12

Absolutely…yes…
and I would think the foot rig would be of great importance.
I just checked the “mancandy” foot rig while learning to get this done…its almost identical…but has one extra step he is doing…which im not sure why…I think a lil more experimentation is needed. to give some more details.
I would love to see tutorials on how people approach shoulders(with and without the scapula) and overall and part by part squash & stretch for characters…if you have already figured these out…it might be great piece for the coming BlenderArt issue.
-Kudos


(thedaemon) #13

Thanks lots for the posts. I’m working on my foot/leg rig right now, and these are great help.