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Thread: Dog Rig

  1. #1

    Default Dog Rig



    Hey guys,
    For a uni module I have to rig a dog model, and sadly I have practically no experience with advanced rigging....All that I have used is the skin modifer ha



    Heres my current progress. Sadly the tripple IK leg is broken and the IK solver spine doesnt work either so I will have to re do them :(



    I plan on using dynamic bones to simulate skin jiggle around the neck area, to use a joystick for both the neck and tounge aswell.

    All in all theres still an awful lot of work to do here :\
    Cheers

  2. #2
    variable WesHowe's Avatar
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    I am of the belief that placing the root joint at the center of gravity (a bit frontwards of the spine midpoint) is the best method for a dog, given that half of their weight is borne at each end, not at one end like a biped.

    With the spine extending backward toward the hips, and frontward toward the shoulders, you can, for instance, easily wag the tail and add the additional hip movements dogs make when enthusiastic while keeping the front half stable.

    <* Wes *>

  3. #3

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    Are you suggesting breaking the spine into 2 spline IK's?

    I was originally planning on having like one spline IK then havine a series of controllers to make it so that you could control the movment in certain areas eg, neck , torso and tail :s


  4. #4
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    Right now you have used a spline_ik for 3 parts of body which they must be separate from each other, for tail there are more advanced techniques which you said you dunno about hardcore rigging, so you can use a FK, or Blend between FK and ik_spline, or whatever setup which can give a good control to animators, and same for neck , make sure you're distributing the rotation from head through neck bones/joints.

    Another thing I noticed in your setup is joint placement, you need to locate them better and more accurate, sometime just some unit wrong can change a reality about that creature skeleton.

  5. #5
    variable WesHowe's Avatar
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    Here is a fully workable dog rig I did:



    You will see there is a root joint on the ground and a cog (center of gravity) joint in the middle of the spine, because I like it that way, rather than both as one joint. The spine extends in both directions from the middle, the shower-hook looking things above are IK handles, as is one for the tail, which is a separate chain, and one on the tongue. Each leg has an IK chain, and with sticky turned on, I can grab the hip handle and move the hips left and right, while the feet and forepart remain stable. By adding specific tail wag movements after that, I can get the effect you see when a dog wags its tail enthusiastically.

    Missing from the picture is a look-at handle, because it is off-screen on the left. I use just a single point for both eyes, when you bring it in closer you get a crossed-eye effect, not as dramatic as in a Mel Brooks movie, but a more realistic look.

    <* Wes *>

  6. #6
    Co-Founder Rigging Dojo bclark's Avatar
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    One thing I want to mention that for a real dog, their center of gravity changes quite a bit, there is some interesting articles I found on this at one time..butwhat I see in rigs like this is that , there is confusion between the "skeleton joint locations" and the rig control location. (http://www.gamasutra.com/view/featur...tools_and_.php a great article talking about this issue for human rigs)


    For a dog you are going to want to have the actual COG rig node to be movable, along the spine.. then you can rig the hips/chest just like you would a regular spline ik spine.
    There are a few ways to do "animated" pivot nodes for controllers.

    I just bring this up because I find that there is confusion between skeleton joint placement and animation control placement, they both are for diffrent things, while they often overlap they don't have to match 100%.

    @ one long spline IK- in your drawing, I would keep each section separate, just like on a biped rig/ (head) (neck) (spine) (tail) each would be a separate rig and not influence the next. You will have more control this way and less motion artifacts when trying to pose the character .. vs. having one long system head /spine like your max shot. I like the dog skeleton draw over you did , just build your skeleton to match and you will be off to a good start.

  7. #7

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    EhsanKiani - Thanks man, that makes sense about havinf the neck spine and tail as seperate chains. I was originally going to make controllers to control individual parts but it makes more sense to make them seperate because the tail can move alot more than the neck etc.

    WesHowe - Nice dog it reminds me of that spring dog on Toy Story :)
    Was that done in Maya? I think ill be applying the same tail wagging effect to my dog hopefully

    bclark - Thanks for the reply. Ill have to check out that article and try to relate it to a dog. Ill also have to find out how to go about creating the CoG , by the looks of things its a bone that stems off from the centre of the spine :s

  8. #8
    variable WesHowe's Avatar
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    Yes, in Maya 2011. I am using surface shaders (no texturing) for that cartoon look, so some of the geometry has extra polygons simply for shading purposes.

    Brad knows a lot more than me about the science of rigging, so perhaps my description as COG is misleading. I just want it to look like it is supposed to.

    I rigged an older version of that dog with the default HumanIK skeleton (from the HIK Skeleton generator), just adjusted for the stance and proportions. But it was very tedious to animate tail wagging (and the swaying hips when they walk) because the front half is parented to the back half. I'm much happier with the root in the center.

    If you'll look, you'll see a locator underneath the root. There are actually four parented to a fifth in a setup that allows me to rotate the dog (chase his tail) without the IK twisting the legs like taffy.

  9. #9
    Co-Founder Rigging Dojo bclark's Avatar
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    a cog does not have to be a bone it is just the center of gravity for the rig, on a reg. spline ik chest and hips are independent and animators often start the pose with the COG master control.

    A COG control is just a control object that is the parent over the rest of the rig (ik legs are left out and constrained in /space switched as needed)

    The mid spine bone that Wes did is a workable solution with out requiring more complex rigging.


    I just wanted to try and clear up the distinction between the skinning rig/bones and the controlling objects that are in charge of that skeleton.

  10. #10

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    Thanks for the help so far guys.

    I have been trying to sort out these darrn legs. I have been following Paul Neales tripple IK leg tutorail. Ive gone over it that many time that ive literally memorized it. Im doing everything right , but for some reason when I select the the second HI chain and select and change the solver plan to IK goal it rotates the bones 90 degrees. I re made the leg afew times and it did the same thing :S



    I mirrored the leg and set and linked everything again , made new HI solvers etc and that seemed to fix it. But then when I tried mirroring it back it gets the problem again :S

    Any suggestions as to where im going wrong or a work around for this???

    p.s this is only happeining on the back legs and not on the front legs :s
    Last edited by barnesy; 11-19-2010 at 02:01 AM.

  11. #11
    Administrator Rob Galanakis's Avatar
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    How are you mirroring it?
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  12. #12

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    I managed to sort out this problem by duplicating the working leg through the layer manager. It seems to work fine now.

    I have also created the spline IK spine , neck , and tail as suggested.

    They seem to work fine but the bones stretch at the moment which is something that I will have to sort out aswell



    I have also created some muscles aswell. They are not attatched yet. Im not quite sure what stage I should attatch them at :s



    Next I am going to set up an IK FK blend for the legs and set up some foot rolls etc

  13. #13

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    Quote Originally Posted by Rob Galanakis View Post
    How are you mirroring it?
    Sorry, to answer your question , I was re making the leg each time then trying to reset the scale and transform before applying the HI solvers. But I managed to mirror the bones and helpers together through the layers and the rig is playing nice at the moment :)

    Thanks

  14. #14

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    Today I have been setting up the primary and secondary foot controls and I have ran into afew problems.



    Excuse the rubbish paint over lol

    When I try duplicating the foot bone to apply a wire parameter to it , the bone flips :s , might this be becasuse the bone beneath has had its postition frozen :s

    Also, once I apply the toe bend to the front left leg the bone starts in that posititon. However once adjusting the sliders it will move fine :s

    If anyone can help me out here that would be really appreciated :)

    Thanks

  15. #15
    Administrator Rob Galanakis's Avatar
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    Mirroring is never simple when rigging. Hard to debug from afar, though.

    Making things far more complex is the use of Max Bones. I'd highly suggest just using point helpers instead. Bones in Max are just not worth it, IMO. They hide and provide far too much functionality.
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  16. #16

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    I havea managed to sort out the legs in terms of the linking and foot rolls along with the eye controls as well as the COG.

    I have ran into a couple of problems that are driving me insane though :(

    The first is the Spline IK spine.



    I cant seem to stop the bones from stretching when I move the controlers. In the bone edit tool stretch is turned off :S

    The second is the IK/FK blend for the legs.
    Im really not sure how to go about it as I have already contrained each of the driver bones to solvers and helpers :s



    I have constrained the ik / fk bones to the driver bones and they seem to literally just follow them rather than blen :s

    Any suggestions on these issues will be greatly appreciated
    Thanks
    Last edited by barnesy; 11-27-2010 at 08:34 PM.

  17. #17
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    Quote Originally Posted by Rob Galanakis View Post
    Mirroring is never simple when rigging. Hard to debug from afar, though.

    Making things far more complex is the use of Max Bones. I'd highly suggest just using point helpers instead. Bones in Max are just not worth it, IMO. They hide and provide far too much functionality.
    I never thought about using only helpers and not bones. You maybe got a example that you can show? And isnt the only way to mirror the bones by using the mirror tools in the bone tools dialog ?

  18. #18

  19. #19

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    It's been a while since my last post! , I have reason for my madness, and that reaso is mistakes and corrections likt this one.

    I have just followed Paul Neales tutorial on IK/FK blend arms and applied it to my dog legs.





    Sadly when I applied it I forgot to link up the hand (bottom 2 bones) as I thoght they would follow the bones above....I was wrong.

    I have managed to wire in the paramaters and got it pretty close but its not 100*on the IK :(

    Is this really a problem , as in is it worth a redo of the leg?

    I have also made a new spine neck and tail with much more control. I still have to work on the foot rolls, spring bones and the facial animations then im ready to skin the character.


  20. #20
    Co-Founder Rigging Dojo bclark's Avatar
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    Your new skeleton looks much better, as for re-doing the leg.

    yes it is worth re-doing, so you know it is right, but more importantly, it should go faster the second time and you will learn the information better.

    The faster you redo your mistakes and get them right the better a TD you become.

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