Joints & Limited Range

[vncnt]

In the face of a model I'm using Joints with a Bone Weight Map.

When I activate Limited Range (set to 50mm - deforms nicely) and rotate the skull bone, to move the entire head, unexpected deformation is in the facial area.

I wanted to use a Weight Map to limit deformation to the soft area of the face, not the skull or teeth. And a Limited Range to specify the deformation area.

Does this mean the only option that is left is to create a Weight Map for each Joint (separating the cheeks from the lips from the chin from the forehead, etc) and subtract it from the Face map?

Or is there a better solution?

[Surrealist.]

One thing to keep in mind is joints deform differently than Z Bones. They have a different way of calculating the influence area. It has been a while since I used them, but I do remember it being entirely different.

Just going on memory alone, I found that it took more joints to create the same influence as Z bones. So that might be a factor to look into.

Generally speaking I have not had much luck with limited range with either type of bone. Try using the fall off settings instead first and see how that works. That along with adjusting the number of joints and/or the size.

For more information, I do remember someone posting a facial rig with joints here a while back,. Try to search for that.

[Mr Big]

Check out the Adam rig, in the character animation thread. The rig provided
by Kurt Smith should answer alot of questions you have about weight maps, joints &
joystick control for facial animation.

[Castius]

Joint "influence" the the object in the exact same way as zbones. But they do require more transforms. Since a "a" joint is made up of two transforms. The second transforms defines it's rest-length. This is why you need one more joint at the end of a joint chain to complete it.

Now on to limited range. They should also be the same between bones and joints. However limited range is more complicated than it first appears. LWs bone/joint basically assume every point is influence by ever joint/bone. So if you use limited range to excludes a point from it's influence. That point will behavior uncharacteristic to how you want it to. I don't use limited range unless i'm trying to modifier the falloff. Not limits it's influence. In general i don't use it very much.

Using weight maps to limit bone influence can be very simple. You don't need to paint supper accurate blended weights. Simply paint 100% for every point you want a joints/bones to influence, This is simply use an a include/exclude tools for the joint/bone influence. For example you may have character with legs close to goether. So you may want to paint weight maps for left and right legs. To keep them from influencing each other. In your case it sounds like you might need a weight map for the head then neck/torso.

Whats import to know is that you can apply one weight map to many joints/bones.

[Surrealist.]

Sorry but I am going to have to disagree about joints. You made me open LightWave for a sanity check. Selecting and deselecting Multiply by rest length for a Z bone and a Set of joints is entirely different.

Now under the hood theoretically you may be correct. I have no way to argue such technical issues.

But in application, I found joints deformed completely different. I attributed this to the influence. And I may or may not be correct - technically about that. They may have the same math or influence or whatever. But I distinctly remember being baffled at how different it was in my rig.

In any case, no matter how you look at it, when you rig with joints I found you are looking at a different animal entirely. That is pretty much all I was trying to say.

Rigging with joints and Z bones are two different things entirely and they will not deform the same. If for no other reason than the fact that the theory and practice of rigging with joints is entirely different than Z bones.

So take that into consideration when rigging joints.

[Castius]

This thread is about something very specific. That is limited range and how it affects influence.

Yes Joints can "deform" differently if you set them up to. As they have more features. However in terms of the influence they are the same. So i'm trying to keep it from being confusing as it's confusing enough as it is.

We can take this to another thread if you like. I'm just trying to help vncnt.

[Surrealist.]

I hope you are not seriously thinking I'd bite on that. ;-)

Back to the subject at hand.

This thread as stated is also about weight maps and in general asked for other solutions. I also agree that limited range is not the best solution as I stated in my first post. Fall off is something you can play with as well - as stated. Before turning to weight-maps.

Rigging is very complex.

And vncnt - the reason I suggested that joints deform differently is because it is completely relevant to this thread and the subject. I am not a mind reader. I don't know if you have rigged with Z bones before. "Unexpected deformations" can mean anything. It is relevant to talk about the fact that joints deform differently than Z bones, because in LightWave they can do strange things and I have had the same "unexpected deformations." It could be any number of reasons and if you have been rigging in other packages or in LW with Z bones, it is a relevant discussion. Even if you have never rigged before, joints can be tricky. Just something to keep in mind.

And as for my little sanity test, I did nothing different to the Z bones that I did to the joints other than click the little box.

They do deform quite differently and they behave completely differently if you do nothing. That is my experience with doing quite a bit of rigging with joints.

It is relevant. Well, I don't know if it is because I have not looked at the scene. But it could be. And that is the point. Be aware that there are many things that can effect your deformations.

I am sure you are wise enough not to find this confusing, but just helpful information. :-)

The more information you include about your set up at this point the better.

And again, take a look at facial rigs that have been done. You'll get some ideas.

[Castius]

vncnt i'd say besides using more weight maps the other option is to create more joints. To help define you're influence area.

[vncnt]

It seems I need to add some details.

In the face of a model I'm using Joints with a Bone Weight Map.

These Joints are single point joints, parented to the head. In this case I use the Bone Weight Map to limit facial muscles to soft tissue.

When I activate Limited Range (set to 50mm - deforms nicely) and rotate the skull bone, to move the entire head, unexpected deformation is in the facial area.

Unexpected deformation like air is sucked out of the model. The centre of the joints seem to move with the skull bone but the fall-off area seems to stay behind.

I wanted to use a Weight Map to limit deformation to the soft area of the face, not the skull or teeth. And a Limited Range to specify the deformation area.

When I enable Limited Range and scale it down a little I was able to limit deformation (by using the joint) to a cheek instead of the entire side of the head (initially it was deforming the ear as well).

So far so good.

But now, when I rotate the skull bone the fall-off region of each joint stays behind.

Does this mean the only option that is left is to create a Weight Map for each Joint (separating the cheeks from the lips from the chin from the forehead, etc) and subtract it from the Face map?

Or is there a better solution?

Without the Limited Region the deformation is just too strong so I guess the only option left is to paint a limited region in a Weight Map and subtract it from the soft tissue Weight Map.

If I remove the Bone Weight Map and keep the Limited Region activated it also deforms the teeth.

vncnt i'd say besides using more weight maps the other option is to create more joints. To help define you're influence area.

I already placed lots of single point joints at the lips, cheeks and eyebrows and I hope that will be enough.

I don't know if you have rigged with Z bones before.

Yes. I'm using LW since v4.5 but I never built a complete facial rig before.
The single point joints seemed to work nice in the NT videos.
And my solution seemed to work nice as well until I rotated the head.

I don't like to switch between LW and Modeler to tweak Weight Maps and this solution could have been the answer I guess I was looking for.

"Unexpected deformations" can mean anything. It is relevant to talk about the fact that joints deform differently than Z bones, because in LightWave they can do strange things and I have had the same "unexpected deformations." It could be any number of reasons and if you have been rigging in other packages or in LW with Z bones, it is a relevant discussion. Even if you have never rigged before, joints can be tricky. Just something to keep in mind.

Never used other packages for rigging.
I think the process is tedious and I don't consider this as the fun part.


And as for my little sanity test, I did nothing different to the Z bones that I did to the joints other than click the little box.

They do deform quite differently and they behave completely differently if you do nothing. That is my experience with doing quite a bit of rigging with joints.

It is relevant. Well, I don't know if it is because I have not looked at the scene. But it could be. And that is the point. Be aware that there are many things that can effect your deformations.


I'll try again with Bone Weight Maps only in the next days.
After that I'll check the demo rigs.

Thanks for your replies.

[vncnt]

Check out the Adam rig, in the character animation thread. The rig provided
by Kurt Smith should answer alot of questions you have about weight maps, joints &
joystick control for facial animation.

Thanks for this suggestion.
I'll check this one very soon.

[RebelHill]

There's a lil vid of mine using joints in a face in the 3 free hours package from my tutorials page. Might help you.

[Surrealist.]

Thanks for the info vnct, I was just shooting from the hip there and it looks like I was right.;-). If you are used to Z bones, yep, joints are another animal.

Castius is right though, generally, you need more joints.

But the more complex it gets the more of a problem it is.

Weight maps of course are a good way. But, like you, I don't like going back and forth either. The nice thing about working in Layout is the fact that you have feedback. What I have done is just keep experimenting until something works.

I strongly suggest looking at the other rigs first. Just to get an idea. You can always still use your rigg but apply some of the ideas. I think rebell hill was the one I was thinking of. Not sure.

[vncnt]

Okay, working with Limited Range there is good news and bad news.
When I enable Limited Range and copy the max value to the min value the "unexpected deformation" stopped.
The bad news is that the joint deformation lacks fall-off and makes this type of deformation useless.

But there is more good news.
When I use a new Bone Weight Map for the cheek (single point joint bone) there is no need to subtract it from the "soft tissue" Bone Weight Map (that is used with a Z-bone that moves the rest of the face together with the skull). It even has a nice fall-off without enabling Limited Range.

If all goes well I'll be able to rig the entire face and finally start working on my CA skills with my very own model.

Thanks everyone for your comments!

[Castius]

Glad it's working in your favor now. The magic that happens under the hood can get int he way of working some times. But everyone once in a while it starts to go your way. I like those days.

[vncnt]

Sometimes I wish that NT put this kind of knowledge in a User Manual and add a suggested workflow "to get it done" - would save tons of time.

[Castius]

It's hard to keep track of all the tip and tricks out there. It was nice when there was enough users for people to make those types of books. But it seems that market is pretty dried up.

I however would prefer some of this information was directly visible to the users while they are working. There are even more now with the extra power of joints. In most cases there are some really simply ways to present this information to the users. But the way Layout rigging is designed it simply puts you in the driving wheel and say good luck.

[RebelHill]

Part of the reason its not in the manual is simply because, there are a number of possible workflows. Some are quicker/easier, but with bigger holes and limitations, which is ok when on something with limited needs, and so on and so forth. And it'd be one hell of an instruction book if it contained several variations for doing the same thing.

Which is why some of us wind up doing different trainings, often very different on the same subjects.

As for trying to find/divine a workflow thats a good line to what u want... the best I can give is the passed down advice of, dont think, do the experiment.

In my own training there's section where I witter on (for a good while at times), trying, and systematically picking over different settings and combinations with very simple setups... just a couple bones... simple mesh, subdivided plane or sphere, one or two weights, etc, etc... just to show how to figure out the inner workings, what results derive from what, and then its just a matter of intergrating those solutions that fit the bill u after into the workflow.