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Creating facial hair for character? What method to use when on current pc ram is only 16 gb

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ISUther polycounter lvl 6
I have hickups when creating hair and will get often error that because not sufficient ammount memory Houdini crash. 
When i import my OBJ model in to houdini and do following: 
1. Go to Grooming tab
2. Select my model
3. Click on adds fur (this will take about 1-3 minutes to load)
4. I click on "Initialize Guides" and system crashes. 

As i understand it is because 16 gigs of ram is no good for this job. 
But as i am trying only to add facial hair (so not many hair strings but more like some scattered along the face)
Like you see on this model face

The model i have is this one: 

Is there a way to add sting less of those hairs so system wont crash. (as has to calculate less)
What method would you suggest?

fiber-mesh in Zbrush and then somehow to convert it in Houdini to facial hair? (how?)
I am trying to find a ways to do facial hair without buyng more ram (as i cant afford it at the moment) 

Replies

  • JordanN
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    JordanN interpolator
    It might sound strange but does your renderer support proxies? Or any form of doing instances? 

    I share the same pain of trying to render hair-like objects on limited memory. On 4GB of vram, I've found using grass cards to be highly doable for rendering 200 meter x 300 meter environment.

    While 3D like hair/grass geometry is infinitely better, to help remedy the depth, I've sculpted my grass blades and baked them down to a normal map.

    Another technique I might recommend is using a displacement/bump map to simulate the hair on the face.
  • ISUther
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    ISUther polycounter lvl 6
    I need to investigate it i have no clue. I use Mantra rendering engine (Houdini default).

    Do you have some sample images of result of those methods that you mentioned?
  • JordanN
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    JordanN interpolator
    ISUther said:
    I need to investigate it i have no clue. I use Mantra rendering engine (Houdini default).

    Do you have some sample images of result of those methods that you mentioned?
    Since you're doing characters, check out this guy's breakdown:
    https://www.artstation.com/artwork/6JNyW

    In the 5th image, you see all those blue "dots" on the guy's coat and face. Basically, they're point cloud information representing hair. For performance reasons, instead of showing millions of millions of hairs in the viewport, they're only showing like 1/8th of them in point cloud form.

    Not all instances are the same. For example, instead of dots, they use proxy objects like cubes where only in the viewport do they resemble primitives but the final render uses millions of them.

    Admittedly, it's very hard to describe this process in words, so I recommend watching a video on how proxies/instancing work.
    https://youtu.be/rk8oKYEuVFA
  • Octo
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    Octo polycounter lvl 18
    Where did your model come from (the obj)? If it's from max/maya and possibly zbrush, check your scale.
    You typically need to scale down your object by a factor of 100 in Houdini as it operates in meters by default.
    I think you might be running out of memory because you are trying to cover 100 square meters of face in hair...
  • ISUther
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    ISUther polycounter lvl 6
    Thank you all for feedback i will try it. 
    I sculpted model in zbrush. 
    Also decimated it in this case displacements are baked in to the mesh so cant go lower then 2 million as skinn will loose its resolution this way. 
    I will later try other method (not baking disp maps in to the mesh and getting mesh to houdini and using texture maps)
    in this case i want it as OBJ as i am planing to create VFX effect on top of that mesh and for vfx idea i need actual pollygons as as far as i know i cant build VFX effect (L-system in this case) from textures i need actual pollygons.

    If some one does not know what is L-system here is example: 

    Here is example(In video time frame 32 sec it starts that where moss/plant grows on surface of the object):


    And here also: 



    But thnx Octo i will look in to that meeter thing as yes i remember now that houdini default system is different 
    tho i do not know when i scale model down that will reduce the pollygon face size but keep pollygon faces. 
    so if i scale it down how houdini hair system works. Adds hairstrings (specific ammount to every pollygon face) or if the pollygon face size is bigger does it add more hair strings to that area. I am new to that hair part. 
    Tho i do not want to use zbrush hair as it does not look realistic. 
    And have not seen any good sample for facial hair from zbrush (i am not talking about beard or mustaches but actual facial hair those tiny hair strings that you see when you look male or female face from very close distance) 
  • musashidan
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    musashidan high dynamic range
    Don't use the 2 million deci mesh as the hair location proxy(the geo that the hair grows from) export a much lower level. Trying to compute anything on a 2mill mesh outsude Zbrush will chug your system. Zbrush scale is 100 times smaller than Maya/Max so it should be alright in Houdini, and if it's not a scale issue it's more than likely the dense mesh.
  • ISUther
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    ISUther polycounter lvl 6
    Hey, sry for delay. 
    So i should import to Houdini low poly retopoed version of model and create hair from that?
    As i have not baked out any maps for model all is sculpted and used displacement (baked in to mesh)
    i wanted to build VFX effect on top of the model and this for i need actual details and polygons (not texture files). 
    Can i some how then apply those hairs that i get from low poly model can i apply them to high poly model?
    Keep in mind that goal is after to build vfx effect that flows ober the high detailed model face. 
    Freezing effect or something 
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