Yeti tutorials

This first tutorial goes through the process of creating a fur and groom using peregrine labs Yeti plugin for Maya. I am describing step for step how to go about setting it all up.

In this second tutorial i explain how to make your fur system clump when you have a groom attatched.

I created a simple and straight to the point tutorial series on making a feathery wing.
Check out the details below:


Basic walk through of a few nodes:

This tutorial goes through instancing and creating a feather coat:

This tutorial shows how you can set bounding objects to control of fur should grow or not:

This tutorial goes into controlling a groom through a texture map:

This tutorial goes through setting up your simulation:

This is how to export and import a groom in Yeti

This tutorial explains how to control your hair with a guide curve while animating the mesh.

This tutorial explains how to apply a texture map to a shader and then apply the shader to the yeti node “the fur”.
I also show the settings i usually play with when using V-Ray as my render engine.

This old tutorial was brought back due to a request, it shows how to cache your yeti simulation out.

For more Yeti tutorials have a look at Michael Cauchis page.
Michael explains in very nice detail how to both start a groom and how to manage clumping with Yeti.



261 thoughts on “Yeti tutorials

    • Hi Robert, bussy times I am affraid. If you log on to there is usually someone skilled ready to chip in with guidance at short notice.
      In there you can also upload a .ma file. That makes it much easier to trouble shoot. I can’t tell why your clumping node doesn’t work, but if you feel that your groom is too thin then you need to increase the scatter multiplier. If the clump node does not work then you might need to convert your strands to fibers with the convert node.

  1. Hi Bjorn.
    Thank you so much for going to the trouble of creating these tutorials. There aren’t many resources out there for Yeti and these have helped me a lot.
    I’m currently doing a character with varying hair lengths and am using curves exported from zbrush fibermesh.
    I was wondering if you knew of a way to control the hair length from the curve length?
    using a groom or texture map to drive the lengths is becoming quite time consuming and i was hoping the curve information could help.


  2. Hi bjorn,
    i have some problem to attain hair texture from the body texture in yeti.Iam using arnold hair shader and i have mapped the texture in hair and root color but hair remains same in render.its a repeated question but i dint find a clear answer in the previous ones,hope you can help me.


  3. Hi. there!
    sorry for my poor english. I’m from far east.
    when I trying to render yeti fur include velocity element with maya2015 & vray 3.xx.
    maya shows this message
    // Error: line 1: Exception [module=1] : Rendering region (576,256)-(640,320) //
    // Error: Cannot write output image file “D:/typee/images/tmp/velo_test.exr” //
    // Error: There was a fatal error rendering the scene. //
    how can I fix this?
    maya 2013 & vray is fine.

    • You can’t render velocity pass with yeti, take off this pass , if you wanned this for blur, you have to make 3D blur

  4. Hi bjorn,thank you for making these yeti tutorials. I’ve problem with Guide Curves. I use Yeti 2 with maya 2016, the code don’t work :

    import maya.cmds as cmds

    baseattr = 4.0

    for element in
    attr = cmds.listRelatives(element, s=True)
    cmds.setAttr( (attr[0] + “.outerRadius”),baseattr)

    the error is this:
    # Error: expected an indented block
    Where am I wrong?

  5. Here are the problems I mentioned earlier about low scatter points and clumping issue.

    These are grooms.

    The scatter points here are increased.

    This is the video I tried to copy the method from.

  6. Hello,
    First of all, thank you for all your yeti tuts. It was a really solid base to start learning.
    I manage to make a rat fur with it now, but I’m now stuck with a simple (I guess) pipeline problem… I’ve asked on forum, but I didn’t get any answer by now… So I take my chance here.
    Basicly, I have my Model with fur on It. My friend rigged it and animated it. I’ve exported/imported the model reference, reconnected attribute, import groom cache, the groom form yeti node. But here come the probleme. I made my fur on a model scale at 1. After the animation, the model is scaled à at 0.1… So the groom become giant and has nothing to do with my initial groom…
    I can’t find a way to scale it properly… Tried the Render Lenght and Width, or a scale… But nothing work…
    So I’m here, humbly asking for any clue. 🙂

    Thank you in advance for your time.
    Here an image to explain the problem :

    • Hi Manuel,

      While scaling is a nice freedom in some scenarios it tends to be problematic when it comes to grooms.
      I suggest that you scale the scene in stead of the character.
      Whenever we have to scale models where I work, we always redo the groom, which is why we almost never scale the models or rigs, but make sure from the beginning that it’s the right size.
      If we do scale them it’s typically only by 10%, if you scale it 90% then I don’t think any quick trick can save you… other than scaling the scene/set in stead.


      • Thank you so much for your answer Bjorn. However my fears come true… Problem is that we use it for some crowd simulation and the size is dependant to the simulation. I’ll see with the FX person in order to scale the scene and fix the problem so. 🙂

        Without imposing, I would like to ask an other question about simulation (basic, not yeti simulation) that maybe you could know…
        Let say we have a simulation of 200 rats.. Is there a way to assign the fur without selecting them one by one and import my groom ?
        We try to place the rat with fur in the simulation instancer, but Yeti seems to not like being instanced and crash… The Yeti doc for duplicating fur in simulation is almost non-existant so…

        Thank you so much again for your time and the answer you gave me. You rock. Have a nice day.

  7. Hey there!

    Thanks for the great tuts! Just wondered if you might be able to answer a question…….I’m using Arnold to render a scene and everything seems just fine grooming-wise etc, but when I try to render it says: Error (groomnode0) is missing an attribute; and stops. This is vague enough that I’m unsure how to procede.

    If you any idea what this error means, I’d be grateful if you let me know!


    • I haven’t had that error myself, but check your groom node connections and see if you deleted or changed an attribute to something it can’t find or regonize. Try comparing it to a brand new groom node and see if you can find out what’s different.

    • Can you post a pic of your Yeti Graph ? And the window when you double clic on the groom node ? I can try checking if you want to.

  8. Hi everyone, and thanks for all helpful stuff Bjorn!
    I’ve been playing with Yeti feathers recently and I was wondering if there’s a way to texture a feather as I would do it with a simple plane.
    I am rendering it with Arnold, and what I’ve tried is to type feather_param into aiHair’s U Param and V Param but no luck, just getting weird mirrored result. Guess I am doing something wrong. Thanks!

  9. Hi, does anyone know does airfield works with yeti? for some reason nothing is happening then i add airfield as a force, all other forces are working fine?


  10. Hi ! Thank you so much for your tutorials , it has helped me a lot.
    I’m dealing with yeti simulation right now and I have some issues with kind of lateness. When my character is moving ( not that fast !) the groom doesn’t seem to be able to follow the mesh and it gets one or two frame behind (displaying a straigt line in the viewport) I tried to change every atributs, and nothing can fix this (even iterations.) Have you ever got that issue ? Do you know how to deal with it ?

  11. This is the perfect website for everyone who would like to find out about
    this topic. You know so much its almost hard to argue with you (not that I really will need to…HaHa).
    You certainly put a brand new spin on a subject that’s
    been written about for ages. Great stuff, just great!

  12. Please help me! I get this message whenever I use the clumping node. “( clumping0 in pgYetiMaya1Shape ) No fibres found in second input, clumping will be ignored.”.

      • thank you , i just noticed that using scraggle node is what makes hair move , i dont know why that but hairs move and flicker in render , also using a udim tag in texture node causes a motion blur problem i dont know how to solve this , so hope you can help me if you are free . thank you

  13. something else are feathers i have a problem scattering two different kinds of feather geos , and the second problem is that i cannot map them , any one can share please if you know .

  14. Hi,I got some problem when I tried to use Maya nHair system to simulation pgYetiMaya.
    I used blendshape to influence Yeit’s guideCurves(I use guideCurveSet, not Grooms)than influence my hair.
    My hair would tremble even though the model didn’t move.(If the model moves even worse…)
    I already tried adjust Tip Attraction to 1,Base Attraction to 1,Weight to 10 but still trembling…and the hairstyle will change. completely different style.
    My friend told me that save guides rest position would do but I don’t actually know how to do.
    Hope you can help me out. Thx!!!

  15. I’m new to setting up fur. I’m wondering, could you make any general comments regarding Yeti and Xgen. For example, where is one stronger than the other…which is more robust…also which plays nicer with Renderman? Would you say Xgen is now at the level of Yeti? I know, “it depends”, but but if you could glean any general info that would be really helpful. Thanks.

    • I find that it’s a matter of taste at this point, because you can do great things with both. I personally use XGen these days, because it works across machines without the need for extra plugins. Of course at work we have our own proprietary tools.
      Both systems, Xgen and yeti requires a certain pipeline to work, so you basically need to know both to be able to make your own choice on which is better. Technically they both do a great job. I will say though, that dynamics and simulations seem more controlled in Yeti than in XGen, since in XGen you rely on Maya dynamics and your scene fills up with more nodes, nucleus and stuff. On the bright side XGen is a part of Maya, and you can use familiar tools to control the groom or hair dynamics.
      Whichever you pick is really a matter of taste. I find that XGen is a bit more messy in terms of files saved here and there, but they both yield nice results and good previews.

  16. Thanks for your reply. Much appreciated. How about performance-wise..both interactive and rendering. I’ve found Xgen to be pretty slow in viewport on my machine dual 14-core xeon with a 980ti card. rendering is also kind of slow. other issues i’ve seen so far is fur not wanting to follow the geo around, it seems to “lag” behind…so geo hides fur in some cases. This is with Xgen, no experience with Yeti yet. Thanks.

  17. Hi,i am janakiram from india,i would like to know how to add texture and shading for yati default feathers,i really like the yati feather system
    pls,upload a tutorial.

    Thank you.

  18. Hello there,
    Thanks for the great tuts for the basics. Really helpfull.

    I may have one quick tip for batch tweaking attributes without using script (I’m not sure if it has been posted before so feel free to delete that post if useless) :
    Open the Attribute Spreadsheet in Windows > General Editors.
    Select all the curves you want to modify. Press the ‘Down’ arrow on your keyboard in order to switch the selection to the underlying shape nodes.
    In the Attribute Spreadsheet, go to the ‘All’ tab and scroll all the way at the end.
    Now you can select values per curve, select multiple ones or apply the values to the entire set by clicking the name of the attribute at the top of each column.

    Hope that helps.

  19. hey man, wonderful tutorials, I`ve learn a lot about them, but I don`t know what im doing wrong, i get diferent fur shapes and even no fur calculation at all, when lock density is cheked and when is not, so is there any other parameter that could help me with it, really frustrating because one render and it looks awsome, second render without tweaking anything and no fur! 😦

  20. Hi dear Bjorn

    I have a very big Problem with yeti rendering. I use arnold to render it. I use a vRamp for opacity to transparent the tip of the hairs . but when I use uparamcoord and vparamcoord for texturing the hair I lost v uv coordinate of the hair mean my ramp goes across the v of the model not the length of my hair strands.

    is there a way to smooth the tip of my strands when I use uparamcoord and vparamcoord?

  21. hey man, another question, do you know how to access painted attributes from VrayUserScalar, just like accesing parent_s and parent_t, but with custom attributes.

    • Hi Christian,

      Yes you should be able to connect the clumping node up to the output of the texture node which is getting it’s information from a map. I should have a tutorial on controlling groom with maps.

  22. Hi Bjorn, I was wondering if you had any tips as far as workflow with working on a mesh that is not set in stone.? I know you can use texture reference objects to transfer your groom to a deformed mesh, but is there a way to completely transfer the hair and guides over to a new mesh with the same topology, and then keep working on it? -Thanks

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