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I was following a tutorial on rigging (was pretty much done) and now my entire model keeps spinning around the main root bone if I try to move any bone at all. (first picture is where it originally was and still is while in Rest Position, second image is of how it changes when in Pose Position while in Pose Mode or Object mode, Edit Mode seems fine) enter image description here enter image description here

I tried clearing All Transforms or hitting the ALT+g, s, r while all were selected and that just caused it to spin in the same direction like everything else does as shown in this picture: enter image description here

I was nearly finished with this video tutorial here, https://www.youtube.com/watch?v=QbHAqk7OALw and near the last part my issue began. 2:28:07 was the last time I was in edit mode and the pose was fine. Right after the little turrets he then went and parented 3 more bones and then he switches back to pose mode with no problem, I suspect somewhere in there is where the problem occurred on my end. I could have sworn I followed it correctly but maybe I went wrong somewhere I have no idea.

I couldn't find another issue like mine exactly so sorry if this question has been asked before, I'm still very new.

Edit: I checked in the video comments to see if it had happened to anyone else but I did not see any mention of it unfortunately.

Edit2: Picture for more detail on the yellow lines. enter image description here

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This spinning effect many times is caused by an incorrectly set up IK constraint. Please check the Tutorial again for two things:

  1. to which bone is the target of the IK chain parented to? The target is the bone which you actually move by hand. It must not be a child of the bone chain which is deformed by the constraint

  2. what is the chain length in your IK constraint? By default it is set to 0, meaning the IK constraint affects every bone in the hierachy, so each bone which is a parent of the bone which holds the constraint. Try setting it to 2 for a start and check the deformation. Chain length is the number of bones which are affected by the constraint, including the bone which holds the constraint

chain length setting

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  • $\begingroup$ Thanks for the help. The tutorial already had me set the two yellow bones at the legs to chain length 2. I see yellow lines like in your picture going to the small turrets up top. I dont think I have the option to add pictures on my reply here. I will see if I can add it to the bottom of my original post. Additionally when I first open the project the yellow lines show but if I touch anything they go away unless I click on both the turrets and these same turrets are aiming up slightly off from the handles they are supposed to be aimed at until I switch to edit mode then back to pose mode. $\endgroup$ – yosminkov Aug 26 '16 at 3:14
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As an add-on to Aliasguru's answer, you may have a generic cyclical dependency that your IK modifiers are running into. You can confirm if you do if you go to Windows -> "show console". This option only appears to work on Windows machines, however.

If you do have a cyclical dependancy, you will get an error like

Dependency Cycle Detected:
  'Bone' depends on 'Bone1' through IK constraint
  'Bone1' depends on 'Bone' through parent constraint

If you do see this error, think about how to break the cycle.

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  • $\begingroup$ Thank you. I went to Window->Toggle System Console, that was the closest i saw. I didn't any errors at first, but then I went to edit mode, then back to pose mode right after restarting blender, the stance of mech changed and I see some yellow dotted lines going from the small turrets to the main root and I did in fact get some errors: $\endgroup$ – yosminkov Aug 26 '16 at 2:50
  • $\begingroup$ Dependency cycle detected: main_handle depends on gun_targ.r through IK Constraint. chest depends on main_handle through Parent Relation. gun_target depends on chest through Parent Relation. gun_targ.r depends on gun_target through Parent Relation. Dependency cycle detected: main_handle depends on main_root through Parent Relation. chest depends on main_handle through Parent Relation. gun_target depends on chest through Parent Relation. gun_targ.r depends on gun_target through Parent Relation. main_root depends on gun_targ.r through IK Constraint. $\endgroup$ – yosminkov Aug 26 '16 at 2:51
  • $\begingroup$ Second half: Dependency cycle detected: chest depends on gun_targ.r through IK Constraint. gun_target depends on chest through Parent Relation. gun_targ.r depends on gun_target through Parent Relation. Dependency cycle detected: gun_targ.l depends on gun_target through Parent Relation. chest depends on gun_targ.l through IK Constraint. gun_target depends on chest through Parent Relation. $\endgroup$ – yosminkov Aug 26 '16 at 2:52
  • $\begingroup$ Im thinking it has to do with gun_targ, chest, and main_root then eh? $\endgroup$ – yosminkov Aug 26 '16 at 3:26
  • $\begingroup$ I'm not going to parse that entire chain, because it is meaningless to me, but it sounds like you ran into issue #1 of aliasguru's answer. The last bone of an IK chain cannot be part of a the same parent hierarchy. $\endgroup$ – Kirbinator Aug 26 '16 at 21:18

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