View Full Version : JasonSchleifer_AutoShoulder&FKIKArm
07 July 2003, 05:38 PM
For the one´s who bought the Creature DVD by Jason Schleifer, The Auto Shoulder Setup is quite interesting. But If I want to implement an FKIK Blending like Chris Landreth´s over it???
What is the starting point??? Start from JasonSchleiffer´s and add an FK arm??? or the reverse???
07 July 2003, 06:33 PM
You should be able to implement the IK/FK arm just fine. In Jason's rig you have 2 or 3 skeleton's but one of them is your bind skeleton and the same thing with the IK/FK arm, so all you do is parent all your shoulder joints to the bind Clavicle joint, that way when you move the clavicle, all three skeletons for your arm will move with it. You then just set it up like you normally would.
Let me know if I'm not being clear enough.
07 July 2003, 10:41 PM
thanks for the tip... I´lll try... and tell you if works.:buttrock:
07 July 2003, 12:23 PM
the manual ik/fk arm thingy works great for me in conjunction with the jsAutoShoulder. just build all your arms you need to do the ikfkBlending and the connections to the bind arm. hide and lock all the stuff you do not need to see and parent them arms and your fkControls to your clavicle bone. after that just do the jsAutoShoulder Setup. the drawback might be that your fk-arm does not work with the autoShoulder, because it is an ik-issue. anyway if you want to use fk, you want to animate fk, right?
just my 2 cents.
07 July 2003, 08:04 AM
just a quick question, when doing Jason Schleifers Automated shoulder setup, had anyone had any problems on the right arm, with the Shoudler Aim Start joints flipping if you move the shoulder control in Y?
It works great on the Left arm, but on my right arm, it flips, and i have done exactly the same thing. I'd be happy to send someone my rig so they can take a look at it for me if possible.
07 July 2003, 01:27 PM
nope... never had any flipping probs. did you mirror your joints, or even your complete ik-stuff from left to right? might be a bad idea to scale the whole stuff in negative X. might be the cause for the flipping... also check for correct joint alignments and your rotation orders....
I could take a short look at your rig, if you want to...
07 July 2003, 05:47 AM
In looking at the auto shoulder setup, It looks like you basically are building an aim constraint, aimed at a point that is point constrained between the elbow and roughly the bicep..... am I missing the reason why you actually create bones with IK for the aiming functionality???
Couldn't you also just use a locator, parented to the torso4, aim constrained at a locator that is point constrained between the elbow and bicep?
... and then of course parent the shoulderControl to that?
I found myself also having this thought with the FK/IK spine setup as well..... I guess that I am assuming that there is a reason for using bones to perform these functions even though they are not used for skinning (but merely driving another skeleton)
07 July 2003, 06:33 PM
I could be wrong, but I think it has something to do with just having a nice visual representation. A bone displays exactly where the clavicle would be.
Obviously I am assuming, but it seems logical.
07 July 2003, 07:50 PM
I think that the reason for using a bone and an ikHandle is that you can parent the rest of the shoulder to the bone that is driven by the ik and it remembers it`s original distance (the ik goes to the elbow but the bone keeps its original length) so that your shoulder does not stretch to the elbow but just "aims".
Anyway IK/FK with auto shoulder works fine, but it is the most complicated thing I ever did and my character does not even have legs yet :cry:
07 July 2003, 09:47 PM
I seem to be having an edit undo issue. Granted that I did it slightly different than the tutorial (didn't do the second IK arm bone), but I don't see why that would produce these results.... oh, and Im also using a double elbow.
If I move the wrist controller down and in, and then hit edit undo, the shoulder doesn't orient itself correctly... but if I then nudge either the wrist controller or shoulder controller slightly, it pops (solves) itself back to where it should be.
move wrist control
The "done" file on the CD.. works fine for me.... is there an actual functional need for the second IK arm?
07 July 2003, 06:34 PM
Can someone give me a quick explanation of what this "auto shoulder setup" does. Can't afford Jason's DVD just yet but am curious all the same.
07 July 2003, 08:27 PM
It allows you to drive the clavical animation through the arm IKhandle, in essence automating the animation of that joint.... sometimes we cringe at laying out the money for these DVDs but every one that I have bought is TOTALLY worth it.... this one has tons of useful scripts that saves time... and time is.... well....
08 August 2003, 03:31 PM
you will need the second IK-arm to don't end up in a cycle. when the clavicle is rotated, your ik-arm will follow. if you even have the aiming locators on your first ik-arm the system gets confused because everything will change at once. I think that's why your undo doesn't work either.
with the second ik-arm everything will work fine. because this is the arm where all the aiming stuff is going to happen on. your first arm is parented under the clavicleBone and so the shoulder is moving according to the aiming locators. those locators refer to the second ikArm which is needed to keep the shoulder's original position.
I implemented some extra locators where your shoulder autoAim attribute automatically changes corresponding to the position of the shoulder and the elbow. (jason briefly talked about this issue on his first dvd) so... if I the elbow gets moved up to the shoulder level and even higher, the autoFollow-attribute increases which causes mainly the clavicle to rotate. (try this with your own arm and you'll see what I mean) vice versa when the elbow is below shoulder level autoOrient decreases which causes the shoulder to follow less. (solved that in an expression 'cause driven keys can cause problems when you want to have precise control in all 3 axes).
with this setup you will need the second ik-arm, too, to have your aim behave correctly.
10 October 2003, 05:28 PM
I implemented some extra locators where your shoulder autoAim attribute automatically changes corresponding to the position of the shoulder and the elbow. ...so... if I the elbow gets moved up to the shoulder level and even higher, the autoFollow-attribute increases which causes mainly the clavicle to rotate. .... vice versa when the elbow is below shoulder level autoOrient decreases which causes the shoulder to follow less. (solved that in an expression 'cause driven keys can cause problems when you want to have precise control in all 3 axes).
I am just now getting around to finishing up my entire rig and want to implement what you are talking about.... I tried setting up SDKs on the rotation of the bicep bone but that isn't really working.... can you elaborate (or post a file... or the expression you used) on the approach that you took? I understand the concept, just not sure what values to key off of (translate worldspace values of the elbow locators???).
10 October 2003, 07:11 AM
Where does the IK Pole Vector Control fit into this? If you have a Pole vector control (so you can rotate your elbow...etc) How can your FK/IK switch acount for the placement of the pole vector? it seems to me, that the pole vector would not be able to follow (when you switch back to Ik from Fk.)
10 October 2003, 08:48 PM
Are you refering to the double joint structure (one for FK, one for IK)? or are you refering to the jsFkIk arm setup(single joint system)?... cause the jsFkIkarm doesn't work in itself regardless of the autoShoulder (see this thread http://www.cgtalk.com/showthread.php?s=&threadid=84329).
Otherwise, if its the double joint structure then they would be entirely separate from each other with just a percentage weight of which system you would like applied.
01 January 2006, 04:00 PM
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