View Full Version : Auto-clavicle and no reaction manager

03 March 2011, 11:01 PM
How do I make an auto clavicle that follows the "ik" arm up but not down and I do not want to use the reaction manager? how to extract a relationship to control the clavicle?and what expression or script controller may help me?

I am a Max user.


03 March 2011, 07:17 PM
Use a single joint IK chain from the clavicle to the wrist. This should give you a rotation that you can use as a percentile weight to a constraint giving the auto-clavicle. From there just limit the joint rotation?

03 March 2011, 09:51 PM
thank you

I don't think that limit is going to work on a bone affected by ik for the same reason that I can't wire its rotation, it appears that the ik doesn't rotate the bone in" a direct way" if I can say that.
Besides I need to apply ik on 3 bones (2+end) only.

I just need to know at least what expression or script to be an equivalent to reaction manager.

thank you again

03 March 2011, 06:25 PM
ok then , reaction manager it is, but I thought that if it is possible with reaction manager it is possible with scripted controller or expressions.
reaction manager is slow and unreliable in certain cases.

03 March 2011, 02:45 PM
Here's a cheap way if you want to mimic what Reaction Manager is doing without actually using it.

Apply a script controller on the rotation track you want your clavicle to rotate from. Then create a variable in the script controller which will point to your IK hand control. More specifically, it'll point to the hand control's position track that goes up and down in space. Then you can just create a simple expression that goes something like this:

constantValue = 45 -- When we move our hand control up 45 units, the clav will start rotating. Set this value to whatever you want.
if (val.value > constantValue) then -- Check to see if we moved our hand up pass 45 units
(degToRad (val.value - constantValue) ) -- The value this generates will rotate our clavicle up
else -- Otherwise, if our hand isn't high enough...
0 -- ... Then don't rotate the clav at all

That's a quick and dirty way to set it up.

03 March 2011, 08:20 PM
Thank you for your reply
But basing the rotation of the clavicle on the position of the hand will results in wrong rotations.
I figured out that the best way in this situation is the reaction manager for now at least.

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03 March 2011, 08:20 PM
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