5 ms·

Curly-Cue: Geometric Methods for Highly Coiled Hair

184 points by cainxinth 2y ago

jay-barronville 2y ago
I usually approach “inclusivity”-driven work with a massive amount of skepticism, but as a black man with highly coiled hair, I have to admit I’m very impressed by this research and work. I used to be really into gaming when I was younger, and a somewhat disappointing aspect of many games for me was character selection. Even when there were dark-skinned characters, I can’t think of a single game within which I could select or build a character that truly looked like me (or close enough), and usually, it came down to the hair. At the end of the day, it was never a big deal and I still had lots of fun, but it would’ve certainly been nice to have better, more relatable, selections, so I appreciate this research!
dognaptr 2y ago
Are they just afraid to use the word "afro"?
- SpicyLemonZest 2y ago
  None of the hairstyles depicted in the source link are afros, although I understand why the difference could be confusing if you’re not familiar with type 4 hair. An afro is a specific style where the hair is combed out into a spherical puffball.
dagmx 2y ago
As someone who’s spent a lot of their career working on digital humans and respective tooling, seeing research into curly hair is a breath of fresh hair. It’s really difficult to approximate the same way that straight hair is done and there is definitely a very high amount of Eurocentric R&D in this space, which means anything other than a slight frizz doesn’t move right, and has difficulty in rendering correctly. Hair weight specifically is one that is extremely hard to get right and even harder when it’s wet. I also really recommend watching Theodore Kims talks. He’s ex Pixar and highly respected in the field. He’s done fantastic work in highlighting the lack of research for non-straight hair and non-white skin among other things. This talk has been hugely impactful on me and my own work that many millions of people have seen on the big screen and not realized were digital, in no small part because it highlighted what we were missing. https://youtu.be/ROuE8xYLpX8?si=qUJ0BvcPDyEKOYLk https://youtu.be/ROuE8xYLpX8?si=qUJ0BvcPDyEKOYLk People might not understand the importance, but it’s hugely significant to call out the lack of research so that we as an industry can fill that hole and improve our own work. We need to represent a wide range of digital humans , and a lack of technology/research to represent them means our work doesn’t hold up as strongly.
deleted 2y ago
[deleted]
scoopr 2y ago
[flagged]
- meindnoch 2y ago
  [flagged]
- deleted 2y ago
  [deleted]
fedeb95 2y ago
I wonder if this becomes relevant also in analyzing real hair, for designing hair-related products etc.
- amelius 2y ago
  There is a trillion dollar market in hair, but it is not about virtual models.
  - cscheid 2y ago
    I once heard Pat Hanrahan (who among other things was involved in some of the early realistic hair rendering work) claim that L'Oréal funded some of that work, exactly because they were interested in what the models said about the (control of) appearance of real hair.
  - fedeb95 2y ago
    interesting, why is that? What is that market more into?
- SpicyLemonZest 2y ago
  I’d never rule out crazy applications of math, but the problems seem pretty orthogonal. When you’re rendering, you want to stipulate by fiat that the hair is perfectly healthy and immune to damage and holds its style no matter what the environment brings to bear, and those are exactly the things most hair care products are meant to help with.
Cthulhu_ 2y ago
This presentation by one of the authors is a good primer on the current issues around Black hair and hairstyles in Hollywood, CGI, and video games, and why this research is important: https://www.tkim.graphics/MORETHAN/Darke_Slides.pdf https://www.tkim.graphics/MORETHAN/Darke_Slides.pdf
- burkaman 2y ago
  The core issue: > There have been no papers on afro-textured hair at SIGGRAPH ever. There are over 300 SIGGRAPH papers on other types of hair.
  - samatman 2y ago
    More accurately, there are over 300 SIGGRAPH papers on hair. Slide 3, with this headline: > Curly hair in graphics research is limited to “classical European locks” Contains this phrase: > which varies from an elongated ellipse for African hair Which leads me to think the Eurocentricity of the other 300 papers is being rather oversold. The Beethoven-looking redhead on the previous slide has two hair styles which are unmistakably models of common African hair textures. Being generous I would guess that the hair was made lighter to show details better? Caucasians presenting with that level of frizz is also not unheard of. Afro-textured hair is certainly a topic worth a few SIGGRAPH monographs all on its own, and a dedicated library is also great. But I suspect that a thorough review of the 300 papers in question would find that the insinuation that none of them treat on the subject of African hair is somewhere between "not supported" and "wildly false".
    - wizzwizz4 2y ago
      I'm inclined to believe that the authors, if they quoted that, read it. The implied claim is that this treatment is inadequate. (My reading is supported by the text on the previous slide: page 23 in the PDF.)
    - burkaman 2y ago
      I am not going to read through all 328 papers to fact check this, but I'm very confident they did do a "thorough review", that's how you start research like this. There's a bit more detail in the course that this presentation is from: > As of 2021, we only found two technical papers that showed Afro-textured hair [Bertails et al. 2005; Patrick et al . 2004]. While some technical papers containing Black hair have started to appear since we published our findings [Hsu et al . 2023; Wang et al. 2023], these usually represent relatively unstyled hair. Some styles have started to appear in short talks [Ogunseitan 2022], but a wide range of intricate, sophisticated, and very common hair styles still lie outside the visual language of computer graphics research. - https://dl.acm.org/doi/10.1145/3664475.3664535 https://dl.acm.org/doi/10.1145/3664475.3664535 (not open access, I can share it if you're interested though) The four papers they mention here are not from SIGGRAPH. The "short talk" was from SIGGRAPH 2022, but as that phrase implies it was a talk and not a paper.
zombot 2y ago
This looks great, but 234 Kelvin is almost -40° Celsius. Why so cold?
- pezezin 2y ago
  In the case that people don't understand your comments: uppercase K is Kelvin, kilo should be lowercase k. Plenty of people get it wrong, even researchers and scientists who should know better.
amelius 2y ago
How much processing power does this require? Can it be done in real time?
- throwup238 2y ago
  This is more for movie VFX where rendering times are measured in hours per frame on large rendering farms.
- dahart 2y ago
  This is for hair curve generation, so it can be done offline. Animation and rendering on the resulting models can still be done in real time, to the same degree it could before.
- chefandy 2y ago
  It probably depends on what you mean by real-time. Hair isn't something I deal with a lot, but I'm familiar with the space. It says the top model had a few hundred thousand hairs. Doing real-time flat-shaded grooming in a DCC that supported this type of generation is likely doable. However, I haven't seen any real-time hair simulation that wasn't clever shader manipulation in a game engine or the like. It's just too much geometry (including constraints and self-collisions) for the hardware we have now while simulating everything else. And then you've got to shade all of those individual hairs which wuld have a ton of surface area. It would be super resource intensive.
karmonhardan 2y ago
The short hair example in particular is remarkably realistic. Immediately familiar to this guy who spent most of his childhood with a skin fade, and a massive improvement over the flat image texture or bump maps that are usually used. Because many black people (especially African-Americans) have a mixture of hairtypes, I expect the results to be even better once something like this is implemented alongside existing systems.

184 points by cainxinth 2y ago

I usually approach “inclusivity”-driven work with a massive amount of skepticism, but as a black man with highly coiled hair, I have to admit I’m very impressed by this research and work. I used to be really into gaming when I was younger, and a somewhat disappointing aspect of many games for me was character selection. Even when there were dark-skinned characters, I can’t think of a single game within which I could select or build a character that truly looked like me (or close enough), and usually, it came down to the hair. At the end of the day, it was never a big deal and I still had lots of fun, but it would’ve certainly been nice to have better, more relatable, selections, so I appreciate this research!

dognaptr 2y ago

Are they just afraid to use the word "afro"?

SpicyLemonZest 2y ago
None of the hairstyles depicted in the source link are afros, although I understand why the difference could be confusing if you’re not familiar with type 4 hair. An afro is a specific style where the hair is combed out into a spherical puffball.

dagmx 2y ago

As someone who’s spent a lot of their career working on digital humans and respective tooling, seeing research into curly hair is a breath of fresh hair. It’s really difficult to approximate the same way that straight hair is done and there is definitely a very high amount of Eurocentric R&D in this space, which means anything other than a slight frizz doesn’t move right, and has difficulty in rendering correctly. Hair weight specifically is one that is extremely hard to get right and even harder when it’s wet. I also really recommend watching Theodore Kims talks. He’s ex Pixar and highly respected in the field. He’s done fantastic work in highlighting the lack of research for non-straight hair and non-white skin among other things. This talk has been hugely impactful on me and my own work that many millions of people have seen on the big screen and not realized were digital, in no small part because it highlighted what we were missing. https://youtu.be/ROuE8xYLpX8?si=qUJ0BvcPDyEKOYLk https://youtu.be/ROuE8xYLpX8?si=qUJ0BvcPDyEKOYLk People might not understand the importance, but it’s hugely significant to call out the lack of research so that we as an industry can fill that hole and improve our own work. We need to represent a wide range of digital humans , and a lack of technology/research to represent them means our work doesn’t hold up as strongly.

deleted 2y ago

[deleted]

scoopr 2y ago

[flagged]

meindnoch 2y ago
[flagged]
deleted 2y ago
[deleted]

fedeb95 2y ago

I wonder if this becomes relevant also in analyzing real hair, for designing hair-related products etc.

amelius 2y ago
There is a trillion dollar market in hair, but it is not about virtual models.
- cscheid 2y ago
  I once heard Pat Hanrahan (who among other things was involved in some of the early realistic hair rendering work) claim that L'Oréal funded some of that work, exactly because they were interested in what the models said about the (control of) appearance of real hair.
- fedeb95 2y ago
  interesting, why is that? What is that market more into?
SpicyLemonZest 2y ago
I’d never rule out crazy applications of math, but the problems seem pretty orthogonal. When you’re rendering, you want to stipulate by fiat that the hair is perfectly healthy and immune to damage and holds its style no matter what the environment brings to bear, and those are exactly the things most hair care products are meant to help with.

Cthulhu_ 2y ago

This presentation by one of the authors is a good primer on the current issues around Black hair and hairstyles in Hollywood, CGI, and video games, and why this research is important: https://www.tkim.graphics/MORETHAN/Darke_Slides.pdf https://www.tkim.graphics/MORETHAN/Darke_Slides.pdf

burkaman 2y ago
The core issue: > There have been no papers on afro-textured hair at SIGGRAPH ever. There are over 300 SIGGRAPH papers on other types of hair.
- samatman 2y ago
  More accurately, there are over 300 SIGGRAPH papers on hair. Slide 3, with this headline: > Curly hair in graphics research is limited to “classical European locks” Contains this phrase: > which varies from an elongated ellipse for African hair Which leads me to think the Eurocentricity of the other 300 papers is being rather oversold. The Beethoven-looking redhead on the previous slide has two hair styles which are unmistakably models of common African hair textures. Being generous I would guess that the hair was made lighter to show details better? Caucasians presenting with that level of frizz is also not unheard of. Afro-textured hair is certainly a topic worth a few SIGGRAPH monographs all on its own, and a dedicated library is also great. But I suspect that a thorough review of the 300 papers in question would find that the insinuation that none of them treat on the subject of African hair is somewhere between "not supported" and "wildly false".
  - wizzwizz4 2y ago
    I'm inclined to believe that the authors, if they quoted that, read it. The implied claim is that this treatment is inadequate. (My reading is supported by the text on the previous slide: page 23 in the PDF.)
  - burkaman 2y ago
    I am not going to read through all 328 papers to fact check this, but I'm very confident they did do a "thorough review", that's how you start research like this. There's a bit more detail in the course that this presentation is from: > As of 2021, we only found two technical papers that showed Afro-textured hair [Bertails et al. 2005; Patrick et al . 2004]. While some technical papers containing Black hair have started to appear since we published our findings [Hsu et al . 2023; Wang et al. 2023], these usually represent relatively unstyled hair. Some styles have started to appear in short talks [Ogunseitan 2022], but a wide range of intricate, sophisticated, and very common hair styles still lie outside the visual language of computer graphics research. - https://dl.acm.org/doi/10.1145/3664475.3664535 https://dl.acm.org/doi/10.1145/3664475.3664535 (not open access, I can share it if you're interested though) The four papers they mention here are not from SIGGRAPH. The "short talk" was from SIGGRAPH 2022, but as that phrase implies it was a talk and not a paper.

zombot 2y ago

This looks great, but 234 Kelvin is almost -40° Celsius. Why so cold?

pezezin 2y ago
In the case that people don't understand your comments: uppercase K is Kelvin, kilo should be lowercase k. Plenty of people get it wrong, even researchers and scientists who should know better.

amelius 2y ago

How much processing power does this require? Can it be done in real time?

throwup238 2y ago
This is more for movie VFX where rendering times are measured in hours per frame on large rendering farms.
dahart 2y ago
This is for hair curve generation, so it can be done offline. Animation and rendering on the resulting models can still be done in real time, to the same degree it could before.
chefandy 2y ago
It probably depends on what you mean by real-time. Hair isn't something I deal with a lot, but I'm familiar with the space. It says the top model had a few hundred thousand hairs. Doing real-time flat-shaded grooming in a DCC that supported this type of generation is likely doable. However, I haven't seen any real-time hair simulation that wasn't clever shader manipulation in a game engine or the like. It's just too much geometry (including constraints and self-collisions) for the hardware we have now while simulating everything else. And then you've got to shade all of those individual hairs which wuld have a ton of surface area. It would be super resource intensive.

karmonhardan 2y ago

The short hair example in particular is remarkably realistic. Immediately familiar to this guy who spent most of his childhood with a skin fade, and a massive improvement over the flat image texture or bump maps that are usually used. Because many black people (especially African-Americans) have a mixture of hairtypes, I expect the results to be even better once something like this is implemented alongside existing systems.