View Full Version : hiksolver?

02 February 2011, 12:32 AM
Hey people, I'm using Maya 2010. I've been rigging for quite a while and somehow have never heard of a spring solver (as opposed to a RP or SC IK solver) and so I read up on its documentation and decided to experiment. The reason why I never found it before was because, at least on my Maya, it's hidden by default. To force Maya to recognize it, I wrote ikSpringSolver; in the script editor.

When I went to use the spring IK, I saw a fourth solver that was created when I typed in the MEL command. It's called the hiksolver. At first glance, it doesn't appear to do anything. You move it around and it doesn't affect the joint chain at all. If you rotate a joint as you would in FK mode and then move the handle, the joints don't snap to the IK handle like they would have with a normal IK handle (not that anyone would want to do this typically but you get the point).

The documentation vaguely describes it as a "human IK" that is also used in Motion Builder and only can be used in human IK rigs (which I don't have any knowledge of, to begin with). So my question is how, if possible, is hiksolver implemented in Maya? What is its function primarily?

02 February 2011, 05:08 AM
Look up humanIK in the manual, and you'll find some more info


I've had a play with this, but its a totally different way of rigging, and probably more suited to working along side mocap.


02 February 2011, 02:25 PM
Oh, it's for Mocap? I haven't had an experience in that field of rigging so I wouldn't have known that the two were related. Thank you for the quick explanation!

02 February 2011, 02:29 PM
Human IK of HIKsolver is a one button automatic rig providing you have the proper bones setup with proper labels. It is used for mocap in conjunction with motionbuilder, (it is actually the base for out mocap character pipeline here) but can be used for hand animation if you like. It affects the whole body hence the name i.e. if you pull the arm down the back will arc and knees will bend. There is more info in the docs like djx said, all that is needed is the mapping for joints and labels to make everything work.

03 March 2011, 07:58 AM
Hey, guys,

I, having had problems with the orient constraint/rotation on a particular bone in the leg IK setup of a character I'm rigging, stumbled upon the hikSolver myself. It, to make a long story short, fixed the problem I was having by simply choosing it from the IK Solver pulldown in the IK Solver Attributes section of the Attribute Editor when the handle was selected. Voila!

Having never heard of, much less used, this seemingly-miracle solver, I did some reading up on it myself, and was able to come up with little more than what was mentioned in the prior posts of this thread. I, reluctant to overwrite my previous version for fear of this 'solution' to my problem blowing up at any given time, saved it as a different version and replaced the reference to the old version with the new version in the scenes I'd begun animating the character in. Again, voila.

For all intents and purposes, my problem is solved. I just wanted to know if my using this on a character that has nothing to do with mocap or full-body human IK could result negatively down the anyone's knowledge?

Thanks in advance for any insight.


03 March 2011, 06:12 PM
There is nothing inherently wrong with using the human IK rig for standard animation inside maya. Though it's intent us interoperability between maya and motion builder, the essential purpose of the rig is laying hand animation over other baked animation. Thank being said I would do some tests with the rig before committing to a long project. Be aware that the HIK rig uses full body keys (Ctrl+F), and NOT standard keys. Standard keys will appear to work but will cause problems soon enough. The term full body key also has two meanings, besides essentially being HIK keys there are also keying option accessible from the marking menu when you select a bone that let you either key in "full body" mode of "body part" mode. "full body" mode keys (a type maya full body keys) will key the whole rig, while "body part" mode keys (also a type of maya full body key) will key only the individual bone or chain depending on if you're using FK or IK. I know this all sounds confusing, but that's because the HIK system is basically 3/4 of Motionbuilder crammed into a single node inside maya. For a better idea on controls real the motionbuidler documentation.
Anyway to get back to your questions, there should be nothing wrong with using the HIK rig but it can sometimes be buggy and/or confusing. There is another studio here in the city that does all there hand animation using the HIK rig but inside of motionbuilder instead of maya. The best thing is to do a few animation tests before committing to it.
Hope that wasn't to big of a rant

03 March 2011, 09:44 PM
Thanks, Matthew,

I suppose this will truly be a trial. I'll let us know how it turns out.

Thanks, again


03 March 2011, 10:13 AM
Also remember that in Maya2012 the whole of the HumanIK integration has been completely upgraded. It now has the same UI interfaces and functionality that MotionBuilder has (or most of the functionality). The initial FullBodyIK solvers that went into Maya were a cutdown of the full blown system you now get in 2012.

I'm testing the setups at the moments to see what we could gain from their use through our pipelines here.

03 March 2011, 02:24 PM
This is true mark, I can not wait to get my hands on 2012 just for that reason. Being one of two people that manage the entire mocap process and pipeline here, more stability and functionality between the two would be a godsend as I've most definitely had my fair share of problems on a job at the 11th hour. That being said, mostly everything I said before should still remain true, the HIK rig is the exact same as motionbuilders "control rig". Though functionality and implementation will be no doubt easier and less buggy, I do not believe the mechanics will be fundamentally different. The biggest change besides the updated UI and the new one button exchange is the unification of the two systems. in 2011 the FBIK rig and the HIK plugin were two separate systmes not really meant to be used together even though they served the same purpose. Now that that rigging and retargeting engine are linked in one system there should be much more easily transferrable data.

Mark, are you beta testing 2012? Does the one button exchange really work as intended or is it another example of just because it worked in the demo doesn't mean it will work for you.

03 March 2011, 09:13 AM
From what I've tested so far, as long as the characterizations are good, the retarget is indeed a one button job. Although you're still retargetting onto the HIK rig and not any other production rig... so as long as you're happy animating on the HIK setup, all is now good.

However, like a lot of studios we have a big internal pipeline and proceedural rig around which most of our anim tools are based. We've been thinking about the new HIK setup, especially as we have a nice large in-house MoCap studio using MB. But I'm not sure the animators would be happy switching over to HIK inside Maya?

I still prefer retargetting onto our own setups really, that way we're in total control of what gets sent and mapped to what.

03 March 2011, 01:51 PM
Yeah re targeting to your own rig if your capable of that would definitely be better. Here we are a very small team, only about 8 people. Two of us are mocap and one to two are animators. Because of that the HIK setup is fine for us. There is not much animating over the mocap in maya that is not done already in MB so our animator rarley has to deal with the HIK rig. As for the one button setup I was asking more of sending the character to MB from maya and back rather than the actual rigging and re targeting workflow.

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