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View Full Version : how can we do strechy arm arm and bend arm


blendMinds
12-12-2005, 03:34 PM
hi folks

iam trying strechy& bend arm in messaih iam new due to messsiah i tried so much i haven't got .if any one know explain me or if they are any tutorilas give me the weblink


thanks a lot
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SpikeWorx
12-12-2005, 09:17 PM
Maks has posted some really nice examples of s&s implementation
http://forums.cgsociety.org/showthread.php?t=229745

and his cool foot rig
http://forums.cgsociety.org/showthread.php?t=284909&page=8&pp=15

If you´re just looking for a stretch without maintaining the volume, you can apply an IKTel (without muscle bones) solve after IK2D.
But it´s not nearly as nice as Maks Muscle Bones + IKTel method.

blendMinds
12-14-2005, 09:28 AM
hi

thank alot , i got strechy arm how we can do bend arm. with strechy

when moving the hand ctrl to forward ,bend is getting straight ( with strechy )


what is mak ik tel method?


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*WHAT THE MIND CAN CONCEIVE AND BELIEVE IS WHAT IT CAN ACHIEVE*

maks
12-14-2005, 12:17 PM
Hi blendMinds,

there are different techniques that can produce bendy limbs, depending on your needs. The one I used for my setups is in essence based on curves that are parented to the stretchy bones, and their midpoints are pushed out based on the lower arm angle. I actually used flexmotion in that case. One other possible method I can think of could involve an IK chain of multiple bones (or nulls + muscle bones), where you'd dynamically control the IK stiffness of the individual bones/nulls to either side of the elbow or knee. You could do this e.g. through the IKStiff function, or with one of the functions provided by Mark Wilson's "Dynamic_FUNC" plugin, or Christopher Lutz's "IKParams" plugin.

Tab32
12-14-2005, 05:03 PM
Hi blendMinds,

The one I used for my setups is in essence based on curves that are parented to the stretchy bones, and their midpoints are pushed out based on the lower arm angle. I actually used flexmotion in that case.

This sounds very cool! Do you have a sample of this you could post?

Julez4001
12-14-2005, 11:12 PM
Hi blendMinds,

there are different techniques that can produce bendy limbs, depending on your needs. The one I used for my setups is in essence based on curves that are parented to the stretchy bones, and their midpoints are pushed out based on the lower arm angle. I actually used flexmotion in that case. One other possible method I can think of could involve an IK chain of multiple bones (or nulls + muscle bones), where you'd dynamically control the IK stiffness of the individual bones/nulls to either side of the elbow or knee. You could do this e.g. through the IKStiff function, or with one of the functions provided by Mark Wilson's "Dynamic_FUNC" plugin, or Christopher Lutz's "IKParams" plugin.

cough! Tutorial cough!

blendMinds
12-15-2005, 10:52 AM
hi maks can u explain something about bend arm ? ,
how u did , where should i load that dynamic or ikparm pug-in
samething i want do in maya




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*WHAT THE MIND CAN CONCEIVE AND BELIEVE IS WHAT IT CAN ACHIEVE*

maks
12-15-2005, 11:17 AM
Errr, didn't I already explain above...? :p I'm preparing to leave for christmas holydays, so I don't really have the time right now. Try to do a little research yourself with the hints I gave above, and if you don't succeed I *might* try to do a little example or tutorial when I come back...

Here you can find the mentioned plugins. The IKStiff function comes directly with messiah.

http://www.zoogono.com/plugindetail.cfm?pid=30

http://www.animationsnippets.com/plugins/index.html

bradenbickle
12-17-2005, 03:16 PM
I have a technique that I have been playing with that is similar to what Maks is talking about.

Heres how I'm doing it:

Overview:

You have a heirarchy of nulls that are for all of the IK functions. I cut down on all of the secondary joints that Jow Cosman uses right now just because I can't figure out how to do it right with this method so it comes down to "shoulder, bicept, forearm, wrist".

Between each of those nulls is a muscle bone. For naming purposes I just use the something like this: "bicept_bn" This helps avoid confusion later.

Each of the muscle bones is parented to its respective Null.

Each muscle bone targets the next muscle bone lower in the heirarchy, not the nulls.

Go ahead and create your IK control null out of this heirarchy go to the commands tab.

Setup an IK2D expression using the nulls as the input parameters.
Follow this expression with an IKTel expression. Basically all you have to do here is change the name at the beginning of the expression from IK2D to IKTel and you're done.

Go play with the IK rig.

Now for the fun part. Start pulling on the bones and you can create bizarre shapes while still having the IK do its thing. In the end, it's similar to what flex motion would let you do, but I like only having one effect and the muscle bones can let you do more exagerated movements.

You'll see the IKTel in action when you pull the wrist out of range. As it stands, you'll see that the forearm is being pulled with the hand. It bothers me to have the elbow not stay halfway between the wrist and the bicept so this is where I pull the muslce bones the adjust the elbows position.

Sorry for the long post.

bradenbickle
12-17-2005, 03:18 PM
one little tip I forgot in setting up the nulls to match the bones postions is to copy the rest length of the bones and paste it into the Z pos of the nulls as I go and it positions them exactly at the joints.

blendMinds
12-27-2005, 10:57 AM
hi bradenbickle thank u very much,but iam new to massaih

still iam not getting

Do you have a sample of this you could post?

bradenbickle
12-31-2005, 05:57 AM
I will probably have to wait until Monday to get back with you on this, but I think i can have something for you to play with.

At least you can open it up and deconstruct it. Until then I can walk you through it again knowing that you are new to Messiah.

I do have to ask if you are new to the 3D environment or just Messiah because that too would make a difference in how I explain things.

For Starters do this:

Create a hierarchy of 4 nulls and place them in a pattern that would simulate the positions of a shoulder, bicept, forearm and a wrist. That means they will be spaced apart depending on where you want the elbow joints and the wrist. Are you with me so far?

If so, proceed.

Go to the Effects tab under the Setup tab and while you have the shoulder joint selected, choose "Bone Deform" You'll notice in a window to the right that the bone deform effect has been added to the shoulder Null.

In the "Item List" select the Bone"Deform" effect and look down towards the bottom left of the screen and click on the button that says "Create Bone". A bone has been added to the bone deform effect. Now what you want to do is drag that Bone "in the item list, not the viewport" on top of the Shoulder Null until it turns blue and let go. When you do that it will parent the bone to the Shoulder Null. Then you can adjust the bone's length by clicking and pulling on a little blue ring at the end of the bone in the viewport until it matches the distance between the Shoulder Null and the Bicept Null. (you can also do this numerically in the bone's rest length input field if you like.)



Once you are done with that, move onto the Bicpet bone by selecting the shoulder bone you just created and hitting the + key on the numeric keypad. Take that new bone and parent it to the Bicept Null. Adjust its length to connect to the "Forearm Null", Repeat that for the Forearm Bone parenting it to the "Forearm Null" Just for good measure, create another bone in the same fashion and parent it to the "Wrist Null".

If you get that far let me know and I can move on. As far as naming conventions, I have started naming stuff as follows based on some of Maks's rigs.

(JointName) for nulls
(JointName_bn) for bones

This way I can tell the difference easily when searching for names or typing in expressions.

If you want to proceed a little without me, start making the bones muscle bones by clicking on a bone, looking down in the bone properties area and look for the "muscle bone" button. Click on that, and select the next bone in the hierarchy as the target in the list to the right. Don't click on the nulls as the target, just the bones. Bicept_bn conects to Forearm_bn, Forearm_bn connects to Wrist_bn.

Expressions would be the next step. For that, you are just going to use the nulls to setup your IK2D expressions vs. the bones.

You would only need to create one more null that would be used as the IK Controler or attach null for the expression.

Let me know how this works so far. If you don't need as much explanation or need a little more I'll be glad to do either.

bradenbickle
01-02-2006, 06:32 PM
Okay, here is a file to play with.

I kept it basic, but you could add as many nulls and bones as you like and then really be able to do some strange stuff.

The nulls control the IK

The muscle bones can move independently while the IK still controls the overall movement.

If you have any questions let me know.

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