Help with the Global Control

#1

Hello,

I’m pretty new to rigging so sorry if this sounds a little stupid. I’m having a problem with the control that allows you to move the whole rig around. I’m working on creating a simple rig for a dragon. I’ve set the global control up in the way I was shown to by a tutorial, Parent and Scale Constraints to a group made of controls and the joints and the IKHandles etc.

However when I move the control thus hopefully moving the rig around, the neck and tail joints I’ve made go crazy, I’m pretty sure the foot controls aren’t moving either but I think I know why that is, could be the arms aren’t moving to well also.

I’ve set up the rig so it does work, Spline IK’s for the neck and tail if you need to know. Each part does work I just can’t get it to move around the scene correctly.

I’ve attached some pics (hopefully) that should illustrate my problem

#2

Try setting up a specific hierarchy to hold your rig. Each group should only have the visibility attribute available. I use this for every rig I do.
[ol]
[li]char node (group)[list=1][/li][li] global move (control)[list=1][/li][li]joints (group)[/li][li] iks (group)[/li][li] control objects (group)[/li][li] to transform (group)[list=1][/li][li] transform to show (group)[/li][li] transform to hide (group)[/li][/ol]
[/list]
[li] model (group)[/li][li] blendshapes (group)[/li][li] extra (group)[ol][/li][li] extra to show (group)[/li][li] extra to hide (group)[/li][/ol]
[/list]
[/list]
This hierarchy should eliminate the need to constrain all the parts to a global move, and should move and scale properly.

I hope that helps.

#3

Seems like with the above group hierarchy, you’ll run into problems with double transforms for the spline IK. Being that you’d be grouping the curves and controls objects under the placement node. Unless you put those curves in the extras group

Try keeping your skeleton objects and your control objects in separate group hierarchy’s. Since your control objects manipulate the skeleton, there’s no need for the placement control to directly manipulate any of the skeleton objects. The placement control moves the controls that move the skeleton.

Combing the two is a recipe for double transforms ") keeping things modular is key

#4

Hi again.

I’ve looked at my hierarchy and it doesn’t seem to be that (maybe). Actually the problem seems to lie in my spline IKs, I apologise for not seeing this. I haven’t a clue how to fix it though.

I got rid of one of my splines as a test and parent constrained the controls directly to the joints, now there’s no problem in that section. However I clearly need those spline IKs so I can animate more effectively.

The problem with the tail, for example, is that by moving the control for the hips the hips twist and the tail follows, good for the animating I feel, bad for moving the rig around. The same problem seems to be with the spine as well, by moving the controls I’m moving the IK’s too much.

I’m guessing I need some way of moving the rig around that moves the controls but only effects the IK in such a way that it just follows along, if you get my drift.

Perhaps it is hierarchy problem and I’m just too blind to see it

#5

Yeah, any curves and subsequent clusters would be put in the extras group.
I should have been a bit more clear, because the first time I used this hierarchy, I put the curves under the global move, and got double transforms.

Maybe it’s time for an update on the hierarchy?

#6

Your probably trying to avoid major surgery on the work you’ve done so far, but it may be unavoidable.

Personally, I never use spline ik. I don’t feel an ik solver is needed to achieve what the spline ik does. Softimage illustrates this perfectly.

Constraining nulls to a path, with up vector controls, and then constraining individual joints to each null and binding to those works quite well.

Never the less, create a new scene, and just create one spline ik with the curve/cluster/null controls. Now marquee select everything in the viewport, and translate negative Z. is this what your seeing with your rig?

If your able to, send me the maya file with the rig. Everyframe at me dotcom.

#7

The problem I see with your hierarchy Jacob, is that your grouping object types as opposed to grouping structure. Your nodes reside in groups based on type and not specifically what they aid to/are part of. All the Ik’s live In the same group. But what good is that really? I never work on the left arm and the right leg at the same time. There’s no need to have them grouped together. With this hierarchy, it may seem structured, but all your elements are scattered, and duplicating/reusing any part of the rig will be a mess.

#8

I don’t mind some major surgery, I just don’t know what surgery needs to be done to it. This is literally the third rig i’ve made. The first was direct tutorial and the second was a snake so I’m not nearly experienced enough to know what to do.

I get the nulls to path thing, I don’t understand what up vector controls are though.

Just tried what you suggested, that seems to be exactly the problem. What is causing that?

I’d be happy to send you the maya file. Am I right in guessing the the ‘me’ means repeat your username for your email?

#9

-Removed sensitive info-

#10

the up vector constrains the “Up” “vector” (direction) of any object. In this case. since the Nulls are constrained to the curve, it leaves the nulls subject to flipping since there’s nothing saying “hey, face this direction - always”. You could get down into some nitty gritty stuff and start pulling normals, and tangents from these curves, but an up vector object is the simplest solution, and if you place the up vector object correctly in the hierarchy, you never need to worry about them again. You wouldn’t animate them, they just exist, and make you happy. All the flipping you will ever encounter will be due to improper rotation orders (Gimbal lock), and lack of properly placed upVectors, if any.

That’s basically what the Spline IK is attempting to achieve. Except sometimes it just becomes an asspain and unmanageable. Making them stretch is stupid, and keeping them from flipping isn’t difficult, but it’s just unnecessary. Nulls/locators are your friend. I use them for almost everything, except when I need an IK solution, or something to bind to.

#11

Ok, i’ve had a go at this constraining nulls to path thing technique. I don’t think I get it. Seems like what i’m doing is practically nothing at all.

I get the principal of the idea, just not the application :banghead: . I don’t think what I’m doing to constrain these nulls to a path is correct, also the path doesn’t lock the other joints in place, so when I move a joint the whole chain follows. I’m really sure I’m not doing this at all the correct way, I just don’t get it.

How do I constrain null to path, give me like a rough step by step and I think I can work out the rest. Also a path is just a curve right? That’s what I was taught, if its not then I’m way out

#12

Hahaha, i’ve cracked it! :buttrock:

It was the clusters, I grouped them and placed them in practically every place in the hierarchy I could think of and now it works.

Thank you for all the help guys.

I would still like to know how to do that path thing everyframe just for prosperity sake. Also I sent you the earlier maya file so if you can see anyways of making it better than that would also be great

#13

Very nice. Don’t get me wrong about the spline IK. It has it’s uses. Like mechanical tentacles, or anything where you need that snake like movement. Most the time though, you need it to stretch, or have other functionality. And this is where the null setup takes over. I’ll throw something together later today.

I bet it is a good laugh watching you try to constrain nulls to a path though. "). You’ll have to be more clever to figure that one out, stay tuned.

Best

#14

There are half a dozen ways to do almost everything in Maya. A lot of the time I hear about oh such and such doesn’t work well becuase you can’t do X. When in most cases you can. Setting up squash and stretch on an IK spline is relatively trival once you have done it a few times. Most of the time what hangs people up is some of the linking that you need to do.

If the spine is setup correctly, there really isn’t anything you can’t do with it. A lot of it does however come out to Pre-planning and understanding what you are trying to get out of the rig.

The Spline Null method is not a bad method at all and is really usefull, but you need to remember that both of the methods are nothing more than techniques used to achieve a goal. Knowing more Techniques and how they work will open up more posibilities for how you can achieve something and make it work. Tools for the toolbox.

I’ll get my tutorial back up on line hopefully later this evening (Central Standard Time) which includes the tutorial for Stretchy spine.

#15

I couldn’t agree more. I guess what I was trying to get at, was when you reach the need to make spline IK stretchy, the null/curve method seems to be better suited as it’s quite a simple setup and lends itself to further functionality easier.

Similar to a reverse foot. Some do it with joints, some with nulls/locators. But the null/locator method seems (IMO of course) to open up way more doors and further functionality.

Like you said though, tools in a toolbox. It’s the concepts that are relevant.

#16

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