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View Full Version : Need Help with Reverse Foot Rig and Tilting -- 3ds max 8


Mahlon
05-11-2006, 08:42 PM
I'm trying to setup a reverse foot rig and add side to side tilting, much like Brad Nobles excellent rig. (I'm not sure his is a reverse foot rig, though. Haven't been able to completely figure it out).

Anyway, I didn't have any problem making the reverse bones part. I just didn't know where to insert the "tilt" point helpers in the hierarchy. I did find a place to link them, but I'm not sure if it's the best way to do this. Ultimately, all rotations of the point helpers on the foot will be wired with sliders in PEN Attribute Holder.

If you have time, could one of you rigging gurus take a look at the attached file and see if you think I'll have any problem down the road with the way it's set up now? Or is there a better way?

For now, there are no CA. But you can rotate any of the blue point helpers to see the action.

Thanks a bunch,
Mahlon Bouldin

floyd1510
05-11-2006, 10:32 PM
Hey Mahlon,

Well the only major problem you would face in this rig setup is that when you rotate the foot from the heel downwards (rotate the "P_PNT_HeelRoll_R" helper) the bone flow breaks. This is not good when you skin it. I have created a quick setup and am uploading it (reverse_foot01.zip) with this reply. This might solve your problem. Rotate the light blue colored bones or add controls based on the orientations of the light blue colored bones and finally skin the dark blue colored ones.

Another alternate is to measure the distance between the thigh bone and the foot nub, and write a script keeping the local bone length always equal to the distance. Sorry, i'm not so good at explaining it. I shall create a file and upload it for you tommorow. This will give you a stretchy bone eventually.

Hope this helps,

Vikram.

Mahlon
05-11-2006, 11:54 PM
Vikram,

Hello, Thanks for your reply (and the file). I like your setup.

Attached is a version of my foot with skin bones which would not leave the ankle joint. I'll also need to fix a way for the swivel to follow to follow the foot. Switching parent space to IK Goal is flipping the orientation (maybe I have some bones'/helpers orientation not set correctly).

Thanks again, I look forward to your stretchy example.

Mahlon

omega3d
05-12-2006, 07:19 AM
Ya know what.. I have used both of those setups on different rigs, but I never thought of them on the same. Haha.. Thanks for the idea... Inspiration.

PEN
05-12-2006, 01:26 PM
Well really it isn't both on the same rig as this is no different then a tripple IK leg setup. The bones have just taken place of point helpers that you would like together in the same order anyway. The whole idea of the inverse foot rig is that it stays on the floor and doesn't peel off the ground. I wouldn't say one way is better then the other, they are just different and you would get used to either.

eek
05-12-2006, 06:42 PM
IK wise:

ik from ankle to ball, ball to toe (leave nub)

Make helpers for each ik handle, plus one more slightly bigger at the ball, and one more at the heel position:

"ankle point","ball point","ball point 2","toe tip point","heel point"

Parent ankle ik handle to "ankle point"
Parent ball ik handle to "ball point"
Parent toe ik handle to "ball point 2"

point wise wise:

Parent "ankle point" to "ball point"
Parent "ball point" to "toe tip point"
Parent "ball point 2" to "toe tip point"
Parent "toe tip point" to "heel point"

Now generally you parent the heel point to a main control. And drive the whole lot with an expression or script. If you want to add side to side, id possibly parent the "toe tip point' to one side point, then that side to the other and then finally to the heel point up to the main control. Or you could make a animatable pivot.

This is essential is the 'natural foot' method, i have. I also build in stretching, into this IK, as well as having an FK entire leg. I treat reverse foot, stretch as part of the IK, and have a seperate fk with its own stretch for the FK leg. Then i can match and blend between the two.

eek

virtualmesh
05-12-2006, 06:55 PM
Hi, I've been getting a lot of headway with my riggs, thanks to all you that share your thoughts and experiences and the great tutorials...

My question is somewhat similar to this topic...my monster is not wearing shoes, if it was then I would not consider this to be an issue.

When setting up a simple reverse foot rig, I found that I was in-need of finer control against the two footroll presure points we use on the bottom of each foot, located between the foot bone(s) and the big toe and pinky toe.

With a single bone running straight through the foot (in the simple reverse foot rig), I was finding that my animated foot would pivot in the center of the footroll (just behind the middle toe) and the outer forms of my foot would not stay grounded when the ankle raised up. It's hard to explain but imagin the two 'balls' at the bottom of your feet before your toes, where one would support their body during a footroll. At various points in the footroll, one would shift weight from their outer foot to the inner foot and then back.

So far, my reverse foot rig has the following bone chain (heel>toe>foot>footnub) similar to the one that Paul teaches in his DVD; Considering the foot has it's support on these two foot roll presure points, could the above mentioned reverse foot rig be revised to include:

> bigtoe bone
>>> IK inbetween bigtoe and innerfoot bones (inner presure point)
>>>>> innerfoot bone
> pinkytoe bone
>>> IK inbetween pinkytoe and outerfoot bones (outer presure point)
>>>>> outerfoot bone

then link both the innerfoot and outerfoot bones to a single dummy object (located at the ankle, which is in essence the rear presure point of a foot: three presure points on a single foot, not two - excluding the tip of each toe). this dummy object would then replace the footnub bone within my original reverse foot rig chain.

The rest of the leg could then be joined to the foot rig...
I don't want to refer to using reaction controllers to accomplish this.

anybody have suggestions to what I'm trying to accomplish here?

Mahlon
05-13-2006, 12:40 AM
Thanks eek and Paul,

So are there any practical advantages to rigging one way over the other, I mean in terms of rig behavior, etc. (reverse bones as opposed to 3 IK chains). I've done both and they seem about the same while animating in terms of what you can do. I'm just trying to make sure I don't run into any problems if I stick in a foot tilt -- and wasn't so sure where to do it. But I think I've got it down now, and I've changed the rig to a 3 IK chain. Is it "6 of one, half dozen of the other"?

By they way, Paul, I've almost finished your DVDs and have learned a lot, or rather, gotten more confident with what I suspected, along with new ideas.

Thanks,
Mahlon

PEN
05-13-2006, 01:52 PM
As far as which one is better I ask the animation team what they want. I think that I prefer the tripple IK foot but it doesn't matter what I want, I don't like animating so much any more and tend to only do some here and there.

Have a look at the foot in this mov and you can see a more complex setup for a foot.

http://paulneale.com/technical/troll/troll.mov

Mahlon
05-13-2006, 04:44 PM
Thanks Paul,

That looks good. I will study maxine some more as well. I think I'm getting where I want to be with the rig.

Mahlon

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