Flicky Bones!

[Ben]

I've got a series of about 20 bones in a straight line with an IK Chain controller. This has been rigged to a sort of tentacle. For some reason the bones keep flicking about the place completely eratically.

I've animated the whole bone-structure to slowly move forward while the IK Chain controller waves around a bit, which I would have thought would be no problem. But for some reason the bones keep on flicking about, totally randomly..

Annoying.

Any suggestions?

[Schwinnz]

For that kind of stuff I'd use the SplineIK controller (only max 5).

If you're not using max 5, well, I don't have any idea...

It may be due to the preferred angle on the bones. Bones usually have one preferred direction of bend, (like knees & elbows,) & when you create the bones you should create them with a slight bend in them to define the preferred angle. Obviously this has a problem for things like tails or tentacles, where you may wish to have a straight line of bones with no predefined angle.
As Scwinnz mentioned, spline IK is great for exactly this purpose. Check if your software supports it & if not you may be able to find a script or plugin to do the job.

[kuman]

another thing to try is to use a hose. that object automatically is attached to two objects and flexes. this is probably not what you're looking for in terms of the mesh, especially if you're doing a single manifold peice of geometry, ie something organic. but if you're looking for a fast solution to things like rubber hoses its quick and dirty and will get the job done for secondary elements in a scene.

good luck
-k

[Ben]

Thanks everyone - there's some great food for thought! I've had a really quick go at all your suggested techniques and they all look really helpful.

Kuman - with the Hose, if I was to turn it to Editable Mesh, I assume It'd lose all its physics - is that right?

Thanks everyone again, I'll try the Spline IK too and I'm sure I'll be back with query's on that soon as well!

Cheers all!

[kuman]

yeah that's right

as with all geometry. usually it starts out parametric in max, ie you can change its attributes in the modifier window. but then as soon as you conert it to some sort of poly mesh object you essentially dump out the parametric qualities of it for a static mesh

however something i've started to do more often is using the snapshot tool. this is an excellent way to essentially bake out a peice of geometry from an animation or what not for a single frame render. check it out. its really useful under certain conditions.

-k

[Ben]

Right I've tried the lot and this Spline IK seems to be what I'm after. So, this is different from the regular IK Limb solver in that I manipulate the bones with the Point objects? I hope so as I can't seem to move the IK Chain controller - is that right, or have I set it up wrong?

I'm still intruiged by this Snap-shot idea too. Is it any use for animation or just for taking stills? I don't think I've really grasped its main use. It says in the manual that it's just good for cloning an animated object on different frames to get a stack of identical objects in different positions..

[kuman]

hmm yeah i believe, to the best of my knowledge (disclaimer), that with the spline ik the point is to move the control dummies vs. the actual ik goal.

i also saw that you mentioned the limb solver. perhaps that not what you want to use. there's a few ik options, there's the history dependant one, which is a remanent of the ok 3ds max ik system. the history independant one which is really what's the best solution under most conditions and the limb solver. i think mike-3dt would know much more about this, but i think the limb solver is an ik solution that relies on 2 bones instead of 3 (usually two bones and a nub) and its used for more real time game applications where the number of bones really matter (modern 3d cards can use bones to accelerate animation, i'm not sure bit i think its like 8-16 bones per texture sheet/material id on a real time model, its not much but its much nicer and faster than vertex animation). so i'm not sure if this is what you meant but if you're using the limb solver you should try to use the history independant instead. mike if i got anything wrong here please correct me on this.

as for the snap shot thing. i find it most useful for just gettin a wireframe out for stills but i can see what they are talking about in the sense of having multiple objects with the same modifier stack that's driving animation but each one starting at a different pose perhaps?

good luck
-k

[Ben]

oops - sorry mate, got that a bit wrong! I've not been using the Limb solver, that was a mistake - you know how it is when you're thinking one thing and typing another!

So, yep, I've been using the IKHI Solver which was fine up until recently when I came across this 'flicking' problem. But I've now started using the Spline IK solver which has totally sorted that out, so thanks everyone for that!

I think I should add that I'm probably a realtive new-comer to 3D - I started messing around with it about August 02 and I'm just nearing the end of my first real project at the moment. So there are quite a few things I've still not come across- things like Wire parameters, stuff I've heard about but not actually tried yet.

So I'm sorry if I seem a bit slow to you guys!

Many, many thanks again for all your help- it's much appreciated!

Ben

[mac5er]

need to add swivel helpers