Future of forward/inverse kinematics?

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  04 April 2003
Quote: Originally posted by jschleifer
but you can lock down other parts of hte body besides feet and hands.. for example, an elbow. How many times have you wanted to have a character rest their elbow on a table & have to make a funky setup just to handle that case?

The nice thing about mirai's sytem (from what I've seen) is that you can lock ANY part of the body.. not just hands and feet, but fingers, toes, knees, elbows, torso, root, etc etc.


Yep...too many times, that would be so nice, that situation sucks. I like the idea of kinda sculpting animation with an armature underneath in a way.

(Ambient - I was talking about the graph editor in general...not saying there wasn't one involved in any of these cases. I have no idea if Mirai uses something like that. heheh..just in case.)

Keith - That would be an interesting tut. If you have the time and want to, you can count me in on learning something new.
::b.Schulz . CharActeR aNimatoR ::
  04 April 2003
Also with regards to locking down hands, knees, and so on, last year at siggraph, I have been using this script that I modified from Cid newman from his siggraph course.

It is a script that works by using constraints and two targets and an expression that controls their weights so there is no popping at all. It is really great for locking down parts of a character, from character Space, to world space, and very easy to animate.

Anyways, just thought I would through that into the pile of idea's. The script is really great, and I am working on it now to be more versatile, but I am new to mel script so it's very slow, and I am doing it just for fun.

If anyone wants to look at the script just pm me
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  04 April 2003
Quote: Originally posted by jschleifer
I was thinking of an animation which would make any normal maya animator gulp.. and thought that if we could come up with a system that could handle that, then hell.. we'd be on our way.

okay, you have two characters. One is on a moving platform, the other is standing below him. Character A (the one below) runs up to character B (who is throwing apples, pears, and bananas down at character A) and starts trying to jump up onto the platform. After getting pelted a few times in the head, he is able to manage grabbing onto the platform with one hand. Then he swings his other hand on, brings up his leg and using his leg as a brace (i.e. locking down the knee & lower leg), hauls himself up onto the platform. Then he grabs at Character B, grabbing him round the left arm & swinging him around. Character B grabs at Character A, grasping his head & throws him down to the platform (still moving, btw). Then he grabs Character A's foot with one hand & lower leg with his other hand & swings him around, tossing him off the platform down a rocky slope. Character A lands head first, then butt first, then head, then leg, then arm, then does a double-summersault, then lands face down.

okay, so that'd be tough in any package. .but imagine trying to do that while trying to manage all the hierarchy changes which need to take place & all the fk/ik switching.

A simpler animation but still difficult to do with Maya's current fk/ik system:

A guy is sitting at a desk. Frustrated, he puts his elbow on the table, his head in his hands, and slumps his back, pushing the rolley chair that he's in slightly away.


Not to mention in the first case how long that would take to get all your timing and sense of weight in everything (2 characters pulling on each other?) right while testing out the constraining to (characters and moving board). Only to find out later that you have to change one little thing. That would suck. Seems like it wouldn't be "as much as" a nightmare in the sega'/ mirai style of animating with the ability to lock diff. parts down.
::b.Schulz . CharActeR aNimatoR ::
  04 April 2003
Hi Jason, just wondering if you have seen how Motion Builder handles IK/FK blending? I still a newbie to animating in MB but it seems quite powerful. Also it allows you to store poses on the control rig and apply them at any time to any character in the scene. You can also mirror and offset the poses and define what body part remains pined in place. You can create a simple walk cycle with two or three poses.
For a better example you could try DL the MB_i2_04_AnimatingPoses VTM from 3d buzz.com
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  04 April 2003

haven't played with MB myself, but from what I hear it does sound pretty powerful. don't think it runs on Mac tho, does it?
jason schleifer
Animator - http://jasonschleifer.com/
Co-Founder - http://www.nimblecollective.com
  04 April 2003

looks like it does

It also plays FBX files directly in Quicktime
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  04 April 2003
well whaddyaknow.

anyone know if there's a version of FBX which is free for trying it out? I'd love to give it a shot!

jason schleifer
Animator - http://jasonschleifer.com/
Co-Founder - http://www.nimblecollective.com
  04 April 2003
well you can download the FBX plugins from the site.

and the FBX for quicktime

also if you can get hold of digit mag you can get the MB PLE for free.

you can find a load of free FBX content at turbosquid
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  04 April 2003
That is a fantastic proposal Jason. I had to read this entire thread because of that. I plan on becoming a TD when I graduate and I like to hear things like the situation you posted. It sounds like you can have a tough time on your hand just doing you second scenario. But the first one. Man! I say just use live actors, no one will notice... will they?
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  04 April 2003
Quote: The great thing about this idea (I don't know if character studio can do this), but you can lock down other parts of hte body besides feet and hands.. for example, an elbow.

Jason while Character Studios IK/FK switching is pretty seamless unfortunately it's nothing like you described in Mirai. Plus it is limited to arms and legs I don't know if this has changed in the latest version but I'm pretty sure it's still only arms and legs. You can see the workflow for CS here. http://www.discreet.com/products/cs/cs_features.html
The method Mirai uses could be incredibly powerful and from my understanding of it there is no setup as well. You simply draw out the bones and they automatically work both like IK and FK. I would love to work with something like that.

Quote: say i animate a characters leg inside the viewport. i use Ik or FK to pose it. i can then after placing a few keys turn on the curve for that joint and i will see a curve inside the viewport as i make it. i would then also be able to use spline like tools to edit the path of the spline. and do stuff like refine it.. delete points.. this would translate to Fcurves.. but in 3d form. much like trajectories.. but would happen more interactively.. and syncd with my skeleton. so if i delete a key in the animation editor.. i would see a vertex in the spline dissapear. stuff like that would be nice.

Ambient-Whisper Max does something like this except it's not interactive like you described. What happens is you can display the trajectories and it allows you to convert it to a spline then back to a trajectory display which changes the motion of the animation. Electric Image also does something similar that is interactive with their curve editor but isn't in 3d. What it does is show you the curve of selected objects next to it in the viewport that you can adjust but it isn't 3d like the trajectory.
  04 April 2003

to everyone, whos not so familiar with kaydara:

On www.3dbuzz.com there are tons (over 9,5 hours !!!!) of training videos about kaydara Motionbuilder. The videos have detailed chapters for importing/exporting in/to Maya.

Just get a LogIn (Its "clean", never got some spam), but Ive heard, You could wait 2 or 3 days, but its definitly worth it

They have also training videos about maya, XSI, 3dsMax ....

Here the list:


Introduction to MOTIONBUILDER
Running Time: 3 hrs, 12 min
Video Codec: DivX 5.0.2
Audio Codec: MP3

Overview: Interested in Animation? MOTIONBUILDER is simply the most powerful animation package on the market today. Learn the basics quickly with this VTM!
1 Introduction
Running Time: 17 min | Size: 21.3 MB

2 Overview of the UI
Running Time: 19.7 min | Size: 12 MB

3 The Viewer Window
Running Time: 17.8 min | Size: 25.7 MB

4 Working with Objects
Running Time: 15.5 min | Size: 14.2 MB

5 Basic Animation
Running Time: 27.3 min | Size: 14 MB

6 Exporting from Maya
Running Time: 33.1 min | Size: 30.7 MB

7 Characterizing
Running Time: 18.7 min | Size: 16 MB

8 Character Controls
Running Time: 21.7 min | Size: 24 MB

9 Animating our Character
Running Time: 18.9 min | Size: 31 MB

10 Importing into Maya
Running Time: 3 min | Size: 8.51 MB


Poses, Timewarps, and Motion Blending
Running Time: 2 hrs, 18 min
Video Codec: DivX 5.0.2
Audio Codec: MP3

Overview: This VTM explores some of the powerful tools that make animating in MOTIONBUILDER a breeze. Learn about Poses, Timewarp cures, Motion Blending, etc.
1 Introduction
Running Time: 8.7 min | Size: 7.24 MB

2 The Clip Art CD
Running Time: 7.8 min | Size: 8.3 MB

3 Pose Controls
Running Time: 26.5 min | Size: 32.5 MB

4 Animating with Poses
Running Time: 17 min | Size: 20.6 MB

5 Timewarp Curves
Running Time: 23.75 min | Size: 23.1 MB

6 Overview of Motion Blending
Running Time: 9.9 min | Size: 10.3 MB

7 Tracks, Takes and Cuts
Running Time: 14.9 min | Size: 17.8 MB

8 Blending Takes
Running Time: 14.1 min | Size: 15.1 MB

9 Blending with Poses
Running Time: 13.7 min | Size: 14.7 MB

10 Conclusion
Running Time: 2.1 min | Size: 5.51 MB

11 MOTIONBUILDER Clipart CD - Full
Running Time: n/a | Size: 165 MB


Running Time: 3 hrs, 34 min
Video Codec: DivX 5.0.2
Audio Codec: MP3

1 Introductions
Running Time: 7.5 min | Size: 8.28 MB

2 Simple Constraints
Running Time: 39.2 min | Size: 31.9 MB

3 Relation Constraints
Running Time: 38.1 min | Size: 25.3 MB

4 Expression Constraints
Running Time: 19.4 min | Size: 15.8 MB

5 Helmet and Wrist Computer
Running Time: 35.5 min | Size: 24.5 MB

6 Backpack and Pistol
Running Time: 12.6 min | Size: 21.4 MB

7 Animation - Rough In
Running Time: 43.8 min | Size: 56.1 MB

8 Animation - Fine Tune
Running Time: 18.7 min | Size: 28.9 MB
  04 April 2003
timelapse video clips done. looks like jasons video will run at about 20 minutes. ill try to make the web version shorter.
encoding it now.
  04 April 2003
schweeeet. Can't wait to check it out.
::b.Schulz . CharActeR aNimatoR ::
  04 April 2003
Hi All,

This is a great thread. I've only just had a chance to download the Sega movie that Jason linked to.
It does look to work in a fashion similar to Character Studio but the IK looks a LOT more advanced. Character Studio IK/FK switch is really simple to use once you know how to work around the not-so-obvious 'quirks' that it has.
You can only really lock down hands and feet in character studio and then rotate around any pivot of the hand or foot ie wrist/finger joints/finger tip or ankle/ball of the foot/toe joints etc. The pivot you select is animatable to so you can switch the pivots from one frame to the next.
The main downfall of the Character Studio rig is the pelvis/root bone. It splits the lateral/vertical/rotation keys. I wish you could just grab the pelvis and move it about but it doesn't work like that. Well not in CS3 anyway, I've yet to move onto CS4.

I like to animate with it as it has a simple clean rig to pose in the viewport, like the Sega system and I do work in a stopmotion stylee I just never realised until now!

I won Motionbuilder in the last animation challenge and I really should get it installed and up and running. The more I read about it the better it sounds.

I'm curious to see the Mirai demo as I've never used it or really seen it for that matter.

I don't know if this is any help to anyone but just thought I'd add my bit anyway.


  04 April 2003
As I mentioned on the cg-char thread related to this one, I think it could be done using the same type of techniques out there now, but implemented internally. ie: each joint has FK and IK solution already on it...and then as an interactive tool some type of notion of the chain you are working on to allow moving OR translating the joint in its FK or IK methods, with the rest of the chain working as it needs to.

Kinda like biped...but with the ability on every joint to lock it down.

As a side note what Keith mentions about the "Pseudo-FK/IK" as I like to call it is really just a reuse of Jason Shleifer's spine rig, where the IK handle is under several FK controls. At least that was the inspiration. So you get IK like normal, but then parent it under FK movers, so you can do either one at all times...very easy and quick to use and setup.
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