Jump to content
Hash, Inc. Forums
Sign in to follow this  
williamgaylord

How to rig a Marshmallow...

Recommended Posts

I've got much to learn about rigging. I've learned a lot about constraints and relationships by developing a tree-growth animation rig (another topic later perhaps). Here is a simple character that poses (pun intended) a bit of a challange (to me anyway). He's a spineless little fellow--a Marshmallow! Basically a head with arms and legs...

 

Marshmallow06.jpg

 

I've worked out rigging the face controls and I've experimented a bit with just one of his arms to learn about fan bones, Smartskin, CP weighting, etc., especially to make the shoulder behave.

 

There are some specific challenges that come with having no hip, spine, and torso.

 

Since he has no waist or neck, his whole head/body has to rotate or swivel. This is one reason his legs are not integrated with the body mesh. I wan't to be able to rotate his body almost as though his bottom was a lazy suzan with the legs attached.

 

It would also be nice if I could do squash and stretch (and bend). How do you do this on a simple character like this without messing up the relative placement of separate parts and adversely affecting animation controls (especially facial controls)? A spine poses a challenge to keeping the eyes and mouth independent, yet properly placed. It seems to me a one-bone "spine" or "head" bone makes the most sense. Is there a way to build a distortion box into the model in some way that doesn't interfere with the other rigging and relative spacial relationship of the separate parts?

 

Bill Gaylord

Share this post


Link to post
Share on other sites

Hey Bill, nice character.

I think you'll come to appreciate the thinking of "rigging starts when you start modelling".... meaning, one can build a mesh that will aid in the rigging process.

Right off the bat, withhout spending too much time thinking about this,

A straight coloum of fan bones from bottom of marshmellow to head.

This could also be a great model to use with distortion boxe attached to the bones.

 

I don't have the time to work it out myself right now, but if anyone has good experience with dboxes, this could be a fun guy to put together....

 

Mike Fitz

www.3dartz.com

Share this post


Link to post
Share on other sites

Thanks, Mike! I can hardly wait to get this guy moving around, but I do want a good rig as I'm likely to do a lot with this guy and his clones. Since he is such a "softy", squash and stretch might be especially handy, even if it is not used in the usual sense of implying mass. In his case it would be more in response to direct pressure. :D

 

Look forward to learning more about the possibilities of AM rigging.

 

Bill Gaylord

Share this post


Link to post
Share on other sites

I was thinking about your rigging problem here and, apart from the fact that a distortion cage could really be the way to go, it uccured to me that you probably needent worry too much about the eyes and things slipping about. Actually, I would say that such movement could be pretty helpfull in getting extra expression in there.

 

If you really are worried about it then maybe you could add some extra geometry around the eyes and arms and things and have that geometry controlled by bones that orient like the limbs/eyes. That way, you could move the limbs/eyes and the marsh mallow would move to follow it. Geometry further away from the limbs/eyes would be weighted so they are effected less.

 

Just some thoughts (probably too late).

Share this post


Link to post
Share on other sites

Thanks, John. It's not too late, by the way. I'll be experimenting some more even if I have already started working on an episode, so any suggestions are welcome. I'll be doing quite a variety of "things" to the Marshmallows as the theme of the series is "Marshmallow Safety Films", where all sorts of (hopefully) very funny accidents happen to the marshmallows. Any ideas on special rigging and special effects that could apply to such "accidents" are quite welcome. Since these little guys are such vulnerable creations, there is a lot of room for creativity here.

 

Thanks!

Bill Gaylord

Share this post


Link to post
Share on other sites

I finished his facial animation rigging and now I'm ready to add the rest of his rigging. Here are the basic requirements:

 

1) Since he has to torso, waist, or hips, his arms must travel with his body/head.

 

2) Since he has no waist, to turn, his body/head needs to rotate as though his bottom was a lazy susan.

 

3) The top part of his legs above what serve as his hip joints need to behave like they are attached to the bottom of the "lazy susan". When the body turns the legs need to stay put, rather than traveling with the body. (This is one reason I did not attach the leg meshes to the body/head mesh.)

 

Other than these special requirements, he can be rigged like a normal character with arms and legs. I'm thinking that two bone--one with "translate to" and "orient like" constraints to the other bone-- would be basis for satisfying these three requirements. One would control the rotation of the head/body and the arms. The other (with the constraints) would be parented to "hip" bones for the uppermost parts of the legs.

 

Now, my question is how this would relate to rigs like Anzovin's TSM2 and the AM2000 rig? How my I go about this?

 

Bill Gaylord

Share this post


Link to post
Share on other sites

Hey Bill, the return of the old marshmallow!

I don't think that there needs to be too much special consideration here. He needs to have a normal bipedal rig.

the trick will be getting parts to bend properly.

Can we have a front shaded wireframe of what you have, that might help people see how the bones might need to be layed out.

 

Mike Fitz

www.3dartz.com

Share this post


Link to post
Share on other sites

Here is the TSM2 bone setup I added today. I used the builder utility to add just arm and leg bones. Then I added a main vertical bone up the middle of the head/body. This bone is parented to the arm bones and the body mesh is assigned to it. Facial control bones are children of it, too. The second, smaller vertical bone is parented to the hip bones and legs. This will be constrained to the bigger bone using "translate to" and "orient like" constraints. Only the roll of the smaller bone will be independent. That way the hips will stay attached to the plane of the Marshmallow's bottom, but the body/head and arms can be rotated about the axis of the bigger bone (roll) independent of the hips and legs. This should give me the "lazy susan" like relationship I'm looking for.

 

Bill Gaylord

MMBonesView01.jpg

Share this post


Link to post
Share on other sites

Okay, so what's the prob again? It looks like your working through it.

I see nothing that looks bad with the bones and where they are so far....

 

Mike Fitz

www.3dartz.com

Share this post


Link to post
Share on other sites

One pointer that might be helpful. I've seen in most rigs, most of the constraints are gathered into an on-off-pose called "constraints" which lets you turn them all on or off from one control. How is that done?

 

Bill Gaylord

Share this post


Link to post
Share on other sites

Open up an action window and set up all your constraints.

Key the const. button at the bottom, all othes off(these are in the bottom left of the screen when the aciton window is up) and then got action on the menu bar and select create pose.

A pose is then created.

Or you could right click on the model and select new pose, on/off or percentage and create from there.

That just skips the step of creating them in action.

 

Mike Fitz

www.3dartz.com

Share this post


Link to post
Share on other sites

So far so good! Everything is working fine and as expected, except for some popping related to a "roll like" constraint in intermediate bones of the shoulders. Have some Smartskin touch-ups to do and then Mr. Marshmallow will be ready for animation. I think I'll have the popping fixed soon and will share the details when I work it out. The "Lazy Susan" idea works like a champ! I am so pleased! :D

 

At each shoulder joint I have a single fan bone with an orient like constraint (50%, store roll off) and a roll like (50%) to the upper arm bone. Works like a champ unless I perform the following sequence of rotations:

 

1) first rotate the arm straight down to the side, thumb pointing forward.

2) next rotate the arm forward...

 

When the arm reaches about level straight forward the intermediate bone's roll suddenly pops. I'll have to look closely to figure out what is happening, but I'm guessing the roll handle of the upper arm bone is crossing a plane where the relative angle between it and the fan bone's roll handle becomes ambiguous. If anybody already knows what is happening and knows a solution, please let me know.

 

Thanks,

 

Bill Gaylord

Share this post


Link to post
Share on other sites

Fixed the popping in the shoulder by using part of the experimental shoulder rig I worked out and posted on the "Marshmallow Safety Film" thread. Basically I used a single fan bone for each shoulder. The parent is the shoulder bone. The fan bone has an "orient like" applied relative to the upper arm bone and set to 50% enforcement with "store roll" off. To get the intermediate shoulder ring associated with this fan bone to "roll" partially when the arm "rolls", I apply an "aim roll at" to the fan bone that points to the middle bone of three bones placed behind the shoulder. One bone stays put as a child of the root or "body" bone. The one to the other side of the target bone is a child of the upper arm bone. The target has bone two "translate to" constraints applied, one to each of the bones to either side (I set the "compensate" button while setting each constraint). The target bone stays halfway between the fixed bone and the one that moves with the upper arm bone. This both assures that the roll of the shoulder joint ring is always less than the roll of the arm, and prevents popping by avoiding ambiguous conditions for the "aim roll at" constraint.

 

The attached picture helps illustrate how this works.

 

Bill Gaylord

Shoulder07.jpg

Share this post


Link to post
Share on other sites

Here is a picture showing the case where I got popping in the shoulder when I used a simple "roll like" constraint instead of this "aim roll at" approach. Without Smartskin touchups, the shoulder still behaves quite respectably. The whole arm can roll 180 degrees or more without ugly kinking.

 

Bill Gaylord

Shoulder08.jpg

Share this post


Link to post
Share on other sites

For easier reference here is the description of how I did the shoulders on the experimental arm I posted in the "Marshmallow Safety Film" thread. I'm still experimenting a bit and will post what I finally use for the actual rig. Trying some simplifications and will let you know how they come out.

 

"Here is what I did for the shoulder. The idea is to make the main shoulder ring pivot like it is fixed to an axel. The next ring is the actual pivot point and acts mostly as a hinge joint. The result is similar to a universal joint that connects two rotating shafts at an angle. This is a simplified shoulder design for simple characters where the shoulder does not really need to be joined to the body. The following picture shows how it works:

 

The "axel" bone is a child of the shoulder bone. It has an "aim roll at" constraint to a target that is in turn controlled by the angle and roll of the upper arm bone. The target bone has two "translate to" constraints--one to a bone that is a child of the upper arm bone and one that is a child of the shoulder bone. This combination allows the arm to rotate forward beyond 90 degrees without the target bone passing to the opposite side of the axel bone. If it did, the roll of the axel bone would suddenly pop to the other side causing a gruesome kink in the shoulder.

 

I use Sonofpat's idea of using several bones with "orient like" constraints around the shoulder ring associated with the pivot point. That does most of the work of smoothing the shoulder mesh. I then give it some final tweaks using a Smartskin on the upper arm bone, setting just four extremes--forward, backward, up, and down. Works great with the TSM2 arm rig!

 

I'll do the same with the hip joints as the Marshmallow has no hips, strictly speaking. ("He has no butt!!!")

 

I may post an animation of the arm rig to show off it's performance."

 

Bill Gaylord

ShoulderRig01.jpg

Share this post


Link to post
Share on other sites

"He's alllliiiiiive!!! He's alllliiiiive!!!" The Marshmallow has been rigged with TSM2.0 with the modifications described earlier. Works great! May do some more tweaks here and there, but on the whole he is ready to rock and roll!

 

Thanks to all who have helped!

 

Bill Gaylord

MMOnTheMove.jpg

Share this post


Link to post
Share on other sites

Just posted a short short featuring the Marshmallow on the WIP forum thread "Marshmallow Safety Films". In this one the Marshmallow only speaks, so I'll have to do another to show off the rest of his rigging.

 

Thanks, y'all for the help and encouragement!

 

Bill Gaylord

Share this post


Link to post
Share on other sites
Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Sign in to follow this  

×
×
  • Create New...