Maya Rig - Character Set // Error: line 0: animCurve creation or connection failed for attribute

Lyrup

I'm quite confused by rigging and I was wondering if there are any experienced riggers around who can share their insights.

I've created a model and a rig for a character and I created a character set called MainCharacter. 
It was created as a clean empty character set, and I only manually added all the desired attributes from the controllers to the character set using "Add to Character Set".

My rig has some IK's, a bunch of driven key setups, and uses various types of constraints.
 
When I press "S"  to globally keyframe the main controller when the character set is active I get the following error for a bunch of different objects:

// Error: line 0: animCurve creation or connection failed for attribute MainCharacter.R_Hand_CTRL_scaleX

There are about 10 controllers in my character set that get this error for their attributes.
When I remove all the attributes mentioned in the errors from the character set, at some point the error stops appearing but then I'm left with a rig where half of my controllers don't work.

I've googled the error and what I've found so far is that the error is usually caused by locked attributes, constraints, driven keys and/or 'cyclical' setups.
I'm quite certain none of the attributes I added to the character set were locked. I tried unlocking them to be sure but it changed nothing.
I guess I've done some things wrong in my rig, but now I'm puzzled why it's wrong.  I just don't get why some constraints work fine while others give me this error.

Any pointers?

Mark Dygert

I've run into that error a few times. I haven't changed how I rig and sometimes it pops up and sometimes it doesn't. Drives me bonkers because I haven't figured out what causes it or a solid fix for it. There are times that I'll redo that part of the rig, test it and get no errors then days later they are back.

Here are somethings I try and usually one or two of them make it stop...

1. Unlock and unhide all of the channels, if the error goes away it's not a big issue, just ignore it.
   
   
2. If your rig has keys on it and you reference it into another scene to do animations, it might not let you set keys for certain things. Usually it gives you a different error message about referenced files not being keyable, but with certain keys like driven keys, on certain controllers, it can spew different errors. Removing all animations from the rig file usually gets them to stop and sometimes clears up this error, but not always.
   
   
3. If you've made significant changes to the rig and it was already referenced into some other animation files you might have some bad nodes or foster parents hanging out causing issues with missing connection. I usually save out the animation and import it into a new scene. Export your animation (File > Atom > Export/Import), set up a new scene with a fresh reference to your rig and import the animation 
   
   
4. Delete non-deformer history. Sometimes an object has a slightly dirty history that needs to be cleared. Sometimes I'll copy the mesh, export it, re-import it, apply default skin, copy weights and delete the old mesh. 
   
   
5. File > Optimize Scene Size. I've had the error show up when I switched versions of Maya and it's because of nodes that changed, usually some rendering or material nodes related to Mental Ray that I don't care about. Running Optimize Scene size removes those nodes. Usually you get some kind of pop up when you first open the file, and when I get that, I sometimes get this error.
   
   
6. Check your namespaces (Windows > General > NameSpace Editor) if you've imported files or merged scenes you might have some wonky name spaces that are causing issues. 
   
   
7. Get rid of all of your animation layers, even the BaseAnimation layer. To do that in the MEL command line in the lower left of Maya type " delete BaseAnimation " and hit enter. It will remove it the BaseAnimation layer which is usually just a blank layer with nothing on it, but if you've been merging layers and collapsing animations it could have some junk data, deleting it will reset the data.

If you find a solid fix or reason please update this thread! Thanks and good luck!

Lyrup

Thanks for your reply Mark,

I've actually managed to 'fix'  the problem for 8 of my 10 errors. The error magically seemed to disappear after I removed the mentioned attributes from the character set and just added them again. I don't remember if I had shut down and restarted Maya before I added them back to the character set... but I'm pretty sure I at least did a 'Save As' in between. I did not have to re-do any of my constraints or IKs for these.

I still get the error for my EyeScaleSlider_R_CTRL and EyeScaleSlider_L_CTRL, so I'm looking into those two now. These are sliders created from nurbs squares that have their translate Y attributes connected with a driven key to the Scale XYZ attributes of the eye joints. I will try simply setting up the driven key over from the start and see if that works. Will update then. 

Very helpful list of suggestions, much appreciated! They don't all apply to my file, but I'll go through them one by one.

1. 
Done, this doesn't seem to be the issue.

2. 
I did still have some keys on some of my controllers before there was a character set, because I had done an animation test with the rig and didn't cleanly remove all those keyframes afterwards. I believe I've since managed to remove them without removing my driven key keys or other keys important for my rig. These junk keyframes however weren't on controllers that gave me the error so I don't think that really caused it either. But I'm not entirely sure.

3.
I haven't referenced my file to any other files yet, and so far I haven't ever done that before, so this shouldn't be the issue in my case either.

4.
Done, also not the issue for me.

5. 
Done, doesn't solve the issue. I haven't switched version while working on this file or added any plugins so I guess it wasn't likely to do much.

6.
My names are clean and unique and nothing is imported. I don't think I use any weird symbols or extremely long names so unless there is a rule I'm unaware of I can't really see what's wrong with my names. I'm not familiar with the NameSpace Editor and I haven't used namespaces.
  
7.
I haven't used animation layers yet.

So going by this list of possible things there is either something to be said for point #2 or the problem is with something else.

Will edit this post later.

Lyrup

Ah. I think I've found and fixed the issue (for my situation).

There were leftover/unused point constraints inside my EyeScaleSlider_R_CTRL and EyeScaleSlider_L_CTRL objects. I erroneously assumed these still had a purpose.
I deleted these and was able to add the Translate Y attribute to the character set and now able to key them without any issues.