Since anisotropic shading can render materials composed of little hairs such as velvet, could it also be used to render a head of hair, the strands of which provide directionality? Or would a model with solely anisotropically shaded hair look flat and unrealistic? Perhaps this technique would be better suited for cartoony art styles, where an anisotropic shader could be applied to polygons simulating separate tufts instead of an entire head of hair. Based on the images of anisotropically shaded objects, I’m also not sure if this technique would be able to completely accurately depict the complexities of shaded hair—strands of hair are slightly translucent, and thus have optical properties such as refraction, reflection, etc.
razvanturcu
Hair is a complex thing to render because of the amount of hairs and interactions between them needed to output something realistic. I found this example online of someone trying to generate realistic hair through Anisotropic BRDF, but as you predicted, it kinda looks flat and unrealistic: https://www.pythonstuff.org/glsl/example_7_anisotropic_highlights.html. However, I think it could be used for something like animations or cartoons. I found an article from Pixar Animation Studios that talks about other methods to simulate hair more realistically: https://graphics.pixar.com/library/Hair/paper.pdf. It looks interesting because they start by looking at each hair individually as "an infinitely thin cylinder". But as they point out, light scattering between hairs accounts in a big part to what the human eye perceives as illuminated hair. So, the "Illumination" part of the paper builds on top of the cylinder model and tries to calculate these interactions between hairs.
S-Muddana
The discussion surrounding the application of anisotropic shading to render hair highlights the complexities inherent in achieving realistic hair simulation. While anisotropic shading can capture directional properties akin to materials like velvet, directly applying it to individual hair strands may yield a flat and unrealistic appearance. Pixar's approach of modeling hair as infinitely thin cylinders lays groundwork for hair geometry simulation, but accurately simulating light interactions between hairs remains crucial for achieving realism. Exploring methods that extend beyond geometry to consider light scattering between hairs, as discussed in Pixar's paper, offers a promising avenue for advancing hair rendering techniques, bringing us closer to lifelike depictions in animations and visual effects.
Since anisotropic shading can render materials composed of little hairs such as velvet, could it also be used to render a head of hair, the strands of which provide directionality? Or would a model with solely anisotropically shaded hair look flat and unrealistic? Perhaps this technique would be better suited for cartoony art styles, where an anisotropic shader could be applied to polygons simulating separate tufts instead of an entire head of hair. Based on the images of anisotropically shaded objects, I’m also not sure if this technique would be able to completely accurately depict the complexities of shaded hair—strands of hair are slightly translucent, and thus have optical properties such as refraction, reflection, etc.
Hair is a complex thing to render because of the amount of hairs and interactions between them needed to output something realistic. I found this example online of someone trying to generate realistic hair through Anisotropic BRDF, but as you predicted, it kinda looks flat and unrealistic: https://www.pythonstuff.org/glsl/example_7_anisotropic_highlights.html. However, I think it could be used for something like animations or cartoons. I found an article from Pixar Animation Studios that talks about other methods to simulate hair more realistically: https://graphics.pixar.com/library/Hair/paper.pdf. It looks interesting because they start by looking at each hair individually as "an infinitely thin cylinder". But as they point out, light scattering between hairs accounts in a big part to what the human eye perceives as illuminated hair. So, the "Illumination" part of the paper builds on top of the cylinder model and tries to calculate these interactions between hairs.
The discussion surrounding the application of anisotropic shading to render hair highlights the complexities inherent in achieving realistic hair simulation. While anisotropic shading can capture directional properties akin to materials like velvet, directly applying it to individual hair strands may yield a flat and unrealistic appearance. Pixar's approach of modeling hair as infinitely thin cylinders lays groundwork for hair geometry simulation, but accurately simulating light interactions between hairs remains crucial for achieving realism. Exploring methods that extend beyond geometry to consider light scattering between hairs, as discussed in Pixar's paper, offers a promising avenue for advancing hair rendering techniques, bringing us closer to lifelike depictions in animations and visual effects.