Author Topic: HOWTO: No-bake Linear keys from an IK solver...in GMax  (Read 351 times)

Legacy_OldTimeRadio

  • Hero Member
  • *****
  • Posts: 2307
  • Karma: +0/-0
HOWTO: No-bake Linear keys from an IK solver...in GMax
« on: December 01, 2012, 07:05:33 am »


               Common wisdom says that there are basically two ways you're going to get your animation done: Either animating in Forward Kinematics (FK) or animating in Inverse Kinematics (IK) and then baking the animations down to Linear keys.

In a nutshell, if you want to animate a kicking motion, FK means you have to move the thigh, then the shin then the foot in order to complete the motion, whereas IK uses a "solver" and all you have to do is move the foot...and the rest of the leg appears to move naturally as a result of an algorithm.

While reading up on something else earlier tonight, I wound up staring at an old message from Ragnarok_MR4 which seemed to indicate there was a pseudo third way.  Where you could use an IK solver and get Linear keys out of it, but without baking.

Here's his message:

Ragnarok_MR4 wrote...
I've found that the best compromise (imho) between smooth animation and keyframe optimization is to use primairily FK animation with an IK rig set up to snap FK to IK pose. Essentially, this method uses a disabled IK chain (i've found that HI-IK works best) to pose the character's limbs then bake that pose into FK motion keyframes using max's snap to IK tool. This way you have near-perfect control over which IK frames are baked to FK and seamless transitions between IK and FK animation.

Another thing to note is that ALL animations in NWN use linear controllers. Attempting to export characters that use bezier or other controller types is asking for trouble. If you MUST use a non-linear controller, you should bake in the necessary keyframes then change the controller back to linear before export.


But the HI-IK solver is only in 3DS Max and I wanted to see if there was a way to do what he indicated, but in GMax.

Here is a very quick, very barebones demo of how to perform that process in GMax, using the IK Limb Solver:
'Image

I cranked this out pretty quickly.  Please let me know if you have any problems with the technique!
               
               

               
            

Legacy_Failed.Bard

  • Hero Member
  • *****
  • Posts: 1409
  • Karma: +0/-0
HOWTO: No-bake Linear keys from an IK solver...in GMax
« Reply #1 on: December 01, 2012, 08:01:10 am »


               I'll definately be giving this method a try.  While I've been pretty happy with the animations I've managed so far, it's pretty time consuming without the benefits of the IK solvers for some of the motions.
               
               

               
            

Legacy_Failed.Bard

  • Hero Member
  • *****
  • Posts: 1409
  • Karma: +0/-0
HOWTO: No-bake Linear keys from an IK solver...in GMax
« Reply #2 on: December 01, 2012, 10:48:37 am »


                 After playing around with it a little bit, I can see how it would have been useful in making animations that involve larger movements, especially the combat animations.

  Just to try it out, I made a quick whirlwind attack animation (clip is here - Assuming youtube stops being so twitchy and posts it).  Arms and legs were handled almost entirely by the IK helpers.  Foot positioning had to be done manually still, as did any pelvis, torso, and rootdummy movements.

  There do seem to be some limitations to the IK helpers.  You can do arms and legs quite well, torso-neck-head somewhat, but you don't seem to be able to handle the cloak and robe parts with it, or at least I couldn't get them to work.  Still, for larger, sweeping motions it's far easier and faster, and I expect even for smaller motions once I'm more used to using them it'll be easier as well.
               
               

               


                     Modifié par Failed.Bard, 01 décembre 2012 - 11:19 .
                     
                  


            

Legacy_OldTimeRadio

  • Hero Member
  • *****
  • Posts: 2307
  • Karma: +0/-0
HOWTO: No-bake Linear keys from an IK solver...in GMax
« Reply #3 on: December 01, 2012, 07:16:28 pm »


               Very nice!

As an FYI all the GMax docs are in the Omnibus, so if you do a search on IK Solvers, for instance, you not only get chatter from the forum archives but GMax help docs on it.  Also, I asked Ragnarok_Mr4 about his rig setup and this was his reply.  As you can see, he favored a mix.