View Full Version : IKBoost Question

09-08-2007, 05:13 AM
Hi all, I have been doing the IKBoost tutorials (thanks very much, fantastic!)

I have made walks, but I feel the walking is a bit wooden, is this because IKBoost is doing FK? My walks with normal IK are smoother and more natural looking, except for the slippage in the feet which I never did manage to fully eliminate, this is entirely eliminated with IKBoost, due to the use of Binding, Bake Spots as shown in the videos, but now th character seems to come to a stop at each step, or bounces aa bit too much, I'm finding it hard to do anything other than a funky walk, when I want more of a surly one! Is this possible using dynamics or something? I'm struggling to find a way other than slowing the walk down, which still seems to accelerate and decelerate between steps more than I'd like -

09-08-2007, 05:39 AM
Block out the walk cycle first to get the overall timing.You can do that two ways: have the character walk in place for the basic walk cycle then use bind motion command to make the character walk forward. Typically I set up bake spots before doing this. From there I usually filter down the excess keys that are applied to the root controller and then copy/paste the walk cycle to get the rest of the walk, After that I bake keys.
So using this method I can rough out a basic walk cycle, get the character to walk forward and then finaize the animation using bake motion.

Another way is to make the character walk in place then move the root forward as needed to get the feet to match to the right spots then bake motion to finalize.

You can also go from pose to pose on the walk cycle and then finalize via bake motion again but this ways a bit trickier.

The animation looking wooden is more of an animator problem as opposed to an issue with the tools. IKBoost allows you to animate using IK or FK at the same time. You need to go back and add in some 2ndary motions and overlapping motions to make it look more organic or natural. The tools are there to make this process much simpler then with other older methods.
Making the walk look surly, angry, sad etc is again, an animator not animation tool issue. Good animation takes lots of practice and work.

Usually if youre having timing issues with your walk cycle its probably because your timing is off in the blocking out phase.

You can stop slippage with the standard IK by going into the graph editor and make the keys linear for the places things need to absolutely stick. This is usually done in the finalzing stage of the animation. IKBoosts way of doing this is easier and more flexible using the bake motion command and setting bake spots while you work.

09-08-2007, 05:58 AM
Thanks Larry, those sound like superb tips, I'll have to delve deeper into all this as suggested! :thumbsup:

09-08-2007, 05:46 PM
Here is a quick test animation, I'm still not sure how to avoid that shift of weight factor between left and right steps - it looks like IKBoost almost freezes the characters animation curves between steps - I see that it doesnt do it mid step (ie. between heel and ball binds) so maybe its my "blanking?" If so - I'm at a loss how altering poses will help = or am I still wrong?

09-08-2007, 06:16 PM
Its not do to any limitation in IKB. Check your motion curves.

09-08-2007, 06:51 PM
OK, thanks again - I'll check it 2moro as got to go to bed (its after 1.30am here) - I cant do much with the main movements, as they are keyed every frame by the binds (the top item in the hierachy is the model itself) - my first resort was to delete the inbetween keys and alter curves, but everything went straight out of kilter sliding feet wise, I was thinking of using bake keys instead of bind, and using IKBoost to pose, followed by much editing in dope sheet / graph editor, but I'm just getting confussed about what exactly to edit - I dont really understand fully the computations IKBoost does - I'm not saying its not good software, clearly its brilliant, with loads under the hood - just that I have little idea what!! For example, would stiffness settings change the function curves, or would weight, spring, viscocity etc? I altered these and made new animations but couldnt really spot the differences, unless that needs to be done before bake / binds, and which joints bones to apply which settings too - I assume stiffness is just to aid posing, while the other dynamics would effect curve shapes - I tried it in graph editor, but saw no change, but then maybe that was because the bind was already applie to the overall model - heigh ho, its late, so I'm rambling, but even fully lucid I find this all a bit tough/

09-08-2007, 07:52 PM
I use bind just to get the character to walk forward. Then I filter the keys on the root (the main character). THEN I go back and bake motion on the feet again BUT ONLY when Im finalizing. Dont worry if the feet slide a bit in between keyframes. Once youre sure that youve got the animation the way you want THEN bake to finalize (lock the feet etc)

09-10-2007, 05:58 AM
Thanks again Larry, not sure I follow your work-flow (my fault not yours) what I'm struggling with today, is why oh why, does my character gradually sink below the ground level after copy and paste keys (within IKBoost) my first and last keys are identical before bind, but not after, hence, when I copy and paste 3 times, (with a floor object on layer 2) he is noticably sinking!

The curve in graph editor for Y axis is mindboggling, like a yo-yo, I guess thats cos of the complex calculations IKBoost is doing, the graph editor itself is a bit of a mystery to me, seems far more complicated than my old software, but then so is LW in general - I think I might spend a few weeks trying to learn it, only to find IKBoost and graph editor dont like each other very much?

09-10-2007, 09:15 AM
The character sinks because you need to bind the contact points that are in contact with the ground at that time.
The heel is a contact point and stays in contact with the ground then the ball of the foot. Each needs to be bound separately. Bind motion can only work on one contact point at a time.
The y channel of your character should be moving up and down in the graph editor since thats the character should be doing to some degree when walking. :)

09-10-2007, 11:38 AM
Well, here I have binded the heel and toe each as expected, the first pic shows the graph before binding ,the seccond, after, both on the main object, as you can see the final key has been moved on the Y axis, this seems to be multiplied when copy and pasting within IKBoost, making the problem exagerate - why oh why??



09-10-2007, 11:56 AM
Maybe my thinking is all wrong, but what I want to see is feet moving and body more or less gliding, I could use IKStop at the hips I spose, only I hadn't wanted to eliminate torso movement, just that it seems too exagerated for what I'm trying to do, I'm not after making "Realism"

Sure in my graph, the main object is not on the floor at the conclusion of each step as it ought to be, but then in posing, I'm bending feet up and down within parameter boundaries of the overall rig and IKBoost is compensating and adjusting, so my feet are on the floor, the body is goig up and down, but for some reason, its going down on the last key - presumably, because of incoming curve calculations which dont exist at key zero - maybe I should try copying an incoming curve at minus 4? (typing here often digs up new ideas for me - if it works, I'll be more than pleased!)

09-10-2007, 04:32 PM
Hi Simon,
By the sounds of things you are over compliating it.

Try working without the Graph Editor, and the Dope Sheet, don't use AutoBind or Bake yet. I know that all sounds weird, but you'll find a lot of freedom to animate when you get used to working without the Graph Editor, and the cumbersome Dope sheet.

Try and get a good grasp on how Bind Motion works before using Bakespots (definitly don't use Bake on it's own yet), ignore BakeSpots for now anyway.

you will only need Bind motion for a walk cycle you should not need Bakespots at all - especially if you want something fluid looking.

Try this:
Make your base poses 3 frames apart, and be careful to get them right. the animation wont work at all unless these are right in the first place.

So that's Contact_L, Down_L, Passing_L, Up_L, Contact_R, Down_R, Passing_R, Up_R and back to Contact_L.

When you are fully happy with these, go over them again and make a close inspection of your contact points, that they are exactly where you want them for every Pose you have drawn.

When you get to that point, post your progress so we can take a look - then we'll move onto Binding.

09-10-2007, 04:44 PM
I've just had a look at the sample you posted, there's nothing particularly 'wrong' with it - it lack smoothness because you have no overlap or drag.

A few other basic tips for walks:
1. Head is at its lowest after the down, not on the down, you can put this on the Passing for now. Same goes for arms - they become straightest after - not on the down. Think of it all as a delayed reaction to gravity.
2. Body and Head are at their straightest and most forward 'angle of attack' during the up, also the torso should twist so that the leading shoulder should really lead.
3. Arms are at their widest (out from hips - not forwards and backwards on the Down)
4. Dont be afraid the exaggerate the down by giving the knees plenty of bend.
5. Same goes for the Up, make the whole body a leaning arrow pointing to the sky, or even arch the back backwards to contrast a forward arch in Downs.
6. Always make sure to get the leg that strikes contact with the ground is dead straight.

Work on those principles for a while and then experiment with changing them one at a time.

09-10-2007, 05:36 PM
Thanks loads for the tips - I will do more 2moro!

Thanks also to Larry - its taken me a while to get what you were saying - I feel a bit thick now, it just took me a while to see whats going on - still loads I'm totally unaware of!

Another drift I noticed is in the x axis, I think because I posed mostly from that side, the overall object ended up drifting as binding compensated, just a little but it adds up times 4 during each cycle - multiplied further by copy and paste!

I'm sure that as the principles of IKBoost become clearer, I will be able to avoid much of this drifting by use of some method or other lol, I dont know what - but I'm sure its out there!! :)

09-10-2007, 05:58 PM
Here's what I did 2nite - (so I can get some sleep!)
I did the usual wak cycle, bake spots / auto bind, then turned off auto bind, went to graph editor and sorted out the keys that were off, then because IKBoost copy and paste keys sometimes were not pasting the entire cycle (dont know why) I copied and pasted in the dope sheet, then back to graph editor to move that 2nd set of keys to maintain my walk (again to avoid re-bakeing my problems) well, at least for now I can get some Zzz's - well it works, I haven't learned about filtering yet, probably a better way to do that I expect.

Thanks omeone for your advice, I'm not ignoring your suggestions - this solution just for tonight - I been an avid reader of IKBoost.com for weeks - I wouldn't have got anywhere without your pages there!
(also have been a reader of the mighty Splinegod's tips here and elsewhere - so thanks again guys!

09-10-2007, 11:18 PM
Colins got some good tips.
The main idea is that you dont bake except as a finalizing process.
I like setting bakespots just to help me to remember and go back. You can always move, stretch or delete them.
Character animation (good CA) takes along time to learn so dont sweat it. Just have fun and keep practicing. I really like that IKB doesnt get in your face and allows you alot of freedom.

09-11-2007, 01:21 AM
Here's what I did 2nite - (so I can get some sleep!)
I did the usual wak cycle, bake spots / auto bind...

To be honest the 'Bakespots & Autobind' workflow is just a fancy looking gimmick, it is only useful for walk and run cycles (which themselves account for very little finished animation) and even on cycles should be used with much reservation...

Same goes for 'Bakespots & Bake Keys', don't use it unless you have a very good reason.

You've got to learn to walk before you can run, and you've got to take one step at a time (unfortunate puns unavoidable).