need help on a weird rig setup... a floppy pencil...

[hairy_llama]

I want to rig a floppy pen/pencil/stick etc. that can be grabbed from either end or the middle and be shaken about and bend from the correct places... with a straight bone chain it is only possible to bend it from 1 end or the other. Anyone have any ideas?

[Rory_L]

Perhaps the PoobySpine plugin would do the trick. it`s just gone up on Flay.

R

[Dodgy]

Or you could use dynamics, a two point poly chain and meta link to link your pencil to the poly chain... :)

[WCameron]

perhaps some kind of expresion on bones. for instance, if you lay your pencil flay, and place bones in it vertically, tie each bone to a ewight mapped section
of the pencil, then depending on wich bone you grab and lift upward, the bones to either side lag behind the selected bone a bit, and so on until the last bone,
so you get a rubber pencil that sags depending on the bone thats selected 9or moves upward first).

i cant for the life of me see how it oculd be set up like that though since I suck at
expressions.

hopefully i explained that right :-)


- Will.

[pooby]

This can be done.. I think

Not with Poobyspine though
Poobyspine will work from one end, but the other will not stay rock solid.

What you need is 3 rigs, One with the root at the top. one in the middle and one at the base.
Then you make a set of bones that actually do the deforming.
.Your deforming bones need to have Orient constraint and point constraint (both with weighting attached to sliders)
Then you can blend your real bones between the 3 rigs as you animate..

There's more to it than this though

If I get time, I'll make you a rig. I like a challenge.

[hairy_llama]

ah, nice pooby. I was on the right track then... I was trying to have multi bone rigs but did not think of that way to blend between them. I'm thinking of this for a cartoon character so squash and stretch would also be good on the pencil. It would be sweet if you made a rig.
I love the way your spine works, I was having a hard time setting it up though. If your pluggy was out I would have used it on this char I am animating right now. I've not tried the pluggy yet but from your site it appears that the spine is perfectly straight with no curve in the bones... Is this right or is it possible to have a curve like a real spine?

[pooby]

I Made a rig.. BUT..I discovered that if you have more than one incidence of orient constraint, and try to blend between them, One doesn't work.
It's a pain when things don't do what they are there for.
(Point constraint works fine wiht multiple incidences)
This puts an end to that idea.

I have another idea based on a stretchy spine.. I think you can find an example in the Self-compensating spine thread.

This can be controlled by either end or middle.

Again, if I have time, I'll make a rig of it.

(about Poobyspine, you can change the shape of the spine after it is setup. You have to switch off IK and Deform. then rotate the spine into shape. Set the bones. and switch everything back on.)

but it's not worth making it exactly like a real spine.. It doesn't really improve things to have it like that.

[hairy_llama]

Strange... I got orient constraint to blend... Check out my scene.
Basicly its setup like this.
1 null object with 2 bone chains say 6 bones each, one going from L to R and the other reversed.
Now to get orient constraint to work on BOTH chains correctly you need to create some extra bones one the second chain. On every bone of the 2nd chain create a new child bone lets call them rotfix. Make this child bone(rotfix) point at its parent using point at target, do it for all bones.
Now you have 3 bone chain things... 1 normal one, a reverse of normal on and a bone chain following the other reverse chain with each of its bones in reverse, if that makes sense....

Now your Pencil object with 1 matching bone chain, 6 bones.
Its bones should orient constraint to the first "normal" chain of your previous bone rig. Set them all up with an expression for a slider null. Create a new orient constraint and set it up to follow the rotfix bones with a reverse value of the other expression.... Create two point constraints, only on the first pencil bone, have them attatch it to the first "normal" bone chain of your other rig and the matching rotfix bone.

Hope some of that makes some sorta sense... I think thats how I did it :)
Here is an examplel scene.
I am not really happy with it as it is, still needs the 3rd rig to rotate both ends from the middle. And its not fun to animate. :(

[HeadCheese]

what about bone dynamics? lock the IK at one end and just move the pencil. then turn on bone dynamics

[pooby]

HI Hairy-Llama,

That's great that you got it to blend.. I think it's because you used expressions on the Weights rather than channel follower. I'll have to remember that in future.

I think your scene was working rather well. Shame you don't find it fun to move about.

[pooby]

I worked out another way of doing it..

This is a REALLY cool discovery.

if you have again 3 sets of bones, but you make them all active, but each about a metre apart.

Then you can make 3 morphs on your pencil that move the geometry to the location of the new bones (the location of their rest position)
if you have on 'after morphs' then the bones will act on the geometry as normal and you can switch between each rig just with a morph!!!

(you have to do it over one frame though)

It's a fabulously cool technique because you could do this with characters and have unlimited rigs in one shot that all do different things..

[hairy_llama]

This is very interesting sounding. I suppose it would be a problem if you had "real" morphs though...

[pooby]

That's what I thought, but no It's fine.