I'm setting up a foot roll on the unit template and i'm getting some strange irreversible flipping when trying to pose constrain the effector of the foot chain to anything, even with Constraint Compensation enabled. This same behavior is displayed even when retargeting motion capture. If I draw a brand new bone chain this problem is non existent, but the rotations are wrong and would require a slew of new animations to accomodate this change.

You can reproduce the chain with these steps (all local rotations):
Draw the two bone chain in the front view(from the top down)
rotate the foot bone to -54 on Y axis, then -100 on X axis
rotate the toe bone to -35 on the Z axis


Has anyone else experienced this flipping issue and found a way around it?

My memory about these things is super hazy, I'm guessing you're making a simple 2D chain and constraining it to the foot right? Could you post pics? The foot controls aren't placed in the skeletons hierarchy are they?

I'll have to think more but still need a little more info. I've made a bunch of character rigs, I even have one for the unit template somewhere, I'll have to look for it on one of the old PC hard drives.

The bones already exists, it's the unit_template_beta. I'm just setting up a control rig for animation, which is in a separate hierarchy and is made up of simple objects constrained to the skeleton. It's a basic control rig, nothing too complex. I can create bone chains that won't flip, but that won't work here because the rotations would be different to those of the unit_template and would require all new animations. I could use a null skeleton but i'd lose the IK functionality. The problem is the effector on the foot chains don't like constraints.

Yeah I figured as much, more than likely because of the way the IK is set up using SI style, rather than 2D/3D bone chain drawing. The way you draw chains, which viewport and how long has a huge effect on the way they behave. What I meant was the way you're making the control chain, the way I always did it was by drawing a chain that follows the foot and using position and orientation constraints to make it work.

I found my rig but it seems the only 2 things I left out since it was incomplete are the foot roll and floor control. Gonna go over my rig creation dvd from digital tutors that I've owned forever that really teaches a lot to refresh my memory on foot roll controls to see if I can help.

Do you plan on releasing a rig or is it just for your own use? Just wondering cause I have this one that I planned on releasing to and don't wanna invade on the spotlight. =p

I'd also be willing to share if you want to take a look at how mine is set up.

I'm not making any control chains, just control objects constrained to the skeleton. Constraints on the effector won't work here no matter how the control rig is set up, unless someone has a workaround for the flipping. I would really like to see how Pandemic set up their rig. This flipping problem puts a damper on my intended foot roll setup.

I do plan on releasing it eventually, and folks could even add/edit/improve how it works if they wish. If you already have something ready then by all means take the stage.

Just a quick thought because you said it works fine if done from scratch and because I just opened the grounddummy and looked. Did you change the kinematic chain from FK to IK for each bone chain?
The grounddummy is set to 0 (FK) while a newly created chain is 1 (IK).

Just a thought

I haven't changed any kinematic properties. If I reproduce their foot bone chain from scratch with the same rotations theirs had it reacts the same way when constraining the effector to anything by flipping the foot and toe bones.
I can get it to work if I draw the bone chain in the right side view without performing unnecessary bone rotations, but that obviously won't work with existing animations.

EDIT
Here's a screenshot of what theirs (on the right) looks like compared to one that works (on the left) Why Pandemic drew the bone chain in the front view is a mystery to me.

Yeah normally you'd want to draw a chain that has bends looking from the side so you can of course get the angle of the joints right but also XSI will make the IK properly.

I think the only way around it is to build a foot chain, rig controls on the newly created foot chain, set up the constraints on the fake foot then constrain the actual skeletons foot to follow the fake one. As long as the rig controls aren't in the hierarchy it wont affect anything in game.

It still doesn't work. The foot bone still flips once the constraints are applied to the toe bone or effector, these locations are necessary for the foot roll to work properly. Parenting is out of the question since we can't alter the hierarchy. It looks like a foot roll won't be possible with the unit template while retaining IK. The silly bone rotations are obviously screwing it up.

I'm still going to experiment with it, will have to wait until after work tomorrow (1900 is EST), will post back when I have something to post, good or bad.

I haven't found a solution to the flipping but I found a way around it that works. I didn't want to touch the unit template skeleton at first but it was the only way I could think to do this.
I created four nulls and matched all transforms to the root, foot, toe and effector of the original foot bone chain respectively, essentially creating a null chain with the same hierarchy and rotations as the original bone chain. This null chain will serve as the new foot bone chain and will be exported as deformers with the unit while eliminating the flipping.
I deleted the original foot chain and drew a new one in the side view while using the null chain as a snap guide. I tweaked the new bone chain with the move joint tool until the translations matched the nulls.
Then I pose constrained the null chain to the new bone chain which gives me back the IK. Now I can create the foot roll on the new bone chain and it will move the null chain.

Did you ever get it fully working? I haven't finished completely setting up the main controller (for some reason my parameter links aren't working) but I have some weird problems and it may be because there is no IK on the foot.

Yeah I got it working, but there's still more to do and it hasn't broken yet, so i'm grateful for that.

Yeah I just realized what I did wrong, I'm a dummy, gonna fix it and check back. =p

Everything on mine was done, just got this, also doing a floor constraint that wont let the feet pass through, very useful. Also thinking about an up vector for pointing the toe.

What did you do about the toe bone? No matter what I do it wont point in the same direction as the fake bone, wants to rotate the opposite way when moving the reverse foot bones.

EDIT: nvm, got it working, have a single controller moving the foot and controlling the roll, it's a foot outline made out of a curve.
You wouldn't happen to be AceMasterMind1 on youtube would you Ace?

Your foot roll looks cooler than mine. Here's my setup so far: The roll control isn't set up yet, that will eventually drive the path percentage so you won't need to open a property page. I also need to set up a ground plane to keep the feet from penetrating it. I was also thinking about having sliders control the animations, where you create a pose then store it and drop them into the Mixer later to combine them.
The foot rig on mine is probably the most complex part of the entire control rig except for the spine. I think i'll use expressions to drive the rotations of those from one chest control.

Yep, i'm AceMastermind1 on YouTube, "AceMastermind" was already taken.

Yeah the slider thing is great, I used it on a rig to control the finger curl, moving the slider all the way would make the character ball it's fist.

I had to use a lot of directional constraints on the null foot chain to get it to move properly and behave more like a 2d chain since it would follow the rig but wouldn't rotate correctly.

Maybe you might know though why I can't seem to fix my up vectors? The ones on the right side of the body stopped working for some reason and even though I delete the operator and set the resolution plane back to default in the kinematic joint panel I can't assign a new up vector. It's super annoying and I just want my chain up vector control objects to work again on the right arm and leg.

EDIT: Got them working but now wondering if you know how to properly constrain the spine bones to a spineCurve object and use it as a controller? All my attempts had undesirable results.

Not sure if this will help your cause or not but it is something I saw on one of my DT lessons.

I was playing around with this and I could constrain the foot effector to an implicit cube no problem but when I tried to constrain the toe effector would get the flip.

What it showed in the lesson was to match the position and rotation of the constraining object to the effector then constrain it. It won't flip. This by itself would work but the controls especially rotation would be all screwy, close to gimble lock etc.

What they did was make another implicit cube match postition of the constraining object then make the it new cube the parent to the constraining object.
Hide the constraining obect and do the animation with the parent cube.

Like I said not sure if it is helpful but it may eliminate the need to make a new skeleton.

We both got it working, just converted the feet to FK null chains with the same transforms as the original feet then just made a new chain and constrained the FK chain to it. The problem though is the bones themselves, they use the old SI3D style IK solver that doesn't work good when doing reverse foot roll. Got no idea why pandemic uses it, so much easier to use the newer XSI IK system where translating the null effector will work for almost anything.

Just trying to get the spine sorted out, then mine will be done, started it many years ago but after getting the reverse foot roll working I got obsessive and overhauled it completely.

LMK if you want the file to see how I did the foot control, has a working floor too, foot controller can't pass through.

EDIT: Everything seems to be working pretty smoothly, had to ditch the floor constraint since every time I rotated the foot controller for roll it raised the foot up along the Y axis.

Anyone who wants to try it out feel free to PM me and lmk if you like it or not. The scene is saved in XSI 5.1 so any version newer should work fine.

I've been playing around with your unit rig and it is really nice, I couldn't break it! I like your foot roll better than mine, yours rolls both forward and back. I also like the way you set up the spine. Theres only a couple things I would add though, rotation controls for the hands and head and a way to rotate the whole foot using the foot controls, but overall you did a superb job on this!

After seeing your rig it made me rethink the one I was working on and I decided to go in another direction, so I scrapped it. I was examining the biped rig generated from the biped guide in XSI and I really like the functionality it has. I'm going to generate a rig from the biped guide matching the unit template then constrain it to the new rig and see how well that works.

Has anyone here tried using the GEAR auto-rigging plugin? I still use Foundation 5.11 and Mod Tool 7.5 which are incompatible with the plugin, so I can't test it.

Yeah I didn't do anything with the head yet but it didn't seem like there wasn't much that could be done really and the hands moving the effector seemed good enough since there isn't much you can do with the hands in this game other than move the wrist.

The pointing of the toe I'm still trying to figure out, I want the whole foot to move when the leg chain up vector moves but most things I've tried haven't worked.

I keep hearing about GEAR but haven't tried it, I do have a student license for Softimage 2012 but I haven't installed it yet, so I only have 5.1 and Mod Tool 7.5.