Perfect Digital Skin 323
ILMfan writes "BBC Technology is describing a new graphics algorithm for creating perfect virtual skin. This technique by graphics wizard Henrik Jensen (the guy who invented photon mapping) is already being used in movies (it was used on Gollum in Lord of the Rings, and it will be used in the soon-to-be-released van Helsing movie). And perhaps more exciting is that several game companies are planning on using it for their next generation games. So John Carmack are you listening? Any chance this can be included in DOOM3? Of course there are endless other opportunities for virtual humans with perfect skin :-)"
Old news... (Score:5, Informative)
The ATI X800 has support for subsurface scattering (Score:4, Informative)
It's gonna make everything look that much sweeter...
Re:SSS (Score:1, Informative)
Re:The ATI X800 has support for subsurface scatter (Score:5, Informative)
http://www2.ati.com/misc/demos/ATI-X800-DoubleCro
http://www2.ati.com/misc/demos/ATI-X800-Subsurfac
It's already here. (Score:3, Informative)
The technology is already available for games, check out the subsurface scattering demo from ATI: http://www.ati.com/developer/demos/rx800.html [ati.com]
Re:Porn Economics (Score:5, Informative)
Re:Games are getting ridiculous (Score:5, Informative)
Re:Old news... (but still very cool) (Score:4, Informative)
This is also mentioned in his book [ucsd.edu], (2001), which I highly recommend to anyone interested in raytracing. It's short and about as easy to understand as photon mapping could possibly be.
He has a lot of stuff on his webpage [ucsd.edu], too, including videos of computer-generated smoke, light through translucent materials, and a good global illumination demo.
For a simpler explaination of what this is all about, there's a photon mapping [wikipedia.org] entry at wikipedia.
-jim
Re:SSS (Score:2, Informative)
Henrik has been a pioneer [ucsd.edu] in developing efficient techniques for representing BSSRDF (bidirectional sub-surface scattering distribution functions).
This [stanford.edu] paper that he published in collaboration with other notable [stanford.edu] people at Stanford was among the first to describe methods of calculating the effects of sub-surface scattering.
Re:i'm shocked (Score:5, Informative)
The original implementation used raytrcing to achieve the effect, to slow for actual production work. Some people from ILM spotted the paper and decided to implement in a way more friendly to production. Originally it was going to be used for Ep. 2, but the research wasn't completed on time. The first time it was applied was for Dobby in Harry Potter and the Chamber of Secrets. Christophe Hery even presented a Stupid RenderMan Trick using shadow buffers that could be applied to SSS. Around that time Ken McGaugh and Joe Letteri left ILM (tough they were involved with this research at ILM) and joined Weta Digital to work on the Two Towers. Consecuently, Hery, McGaugh and Letteri also received a SciTech Academy award this year for finding a way to implement Jensen's SSS in a production environment.
wrong (Score:5, Informative)
He points out on his web page "Photon mapping is quite good at simulating subsurface scattering, but it becomes costly for highly scattering materials such as milk and skin. For these materials it is better to use a diffusion approximation. The diffusion approximation is much faster than tracing individual photons, and it is simple enough that a BSSRDF can be formulated."
Here's a BSSRDF [stanford.edu] from a google search.
Re:The difference (Score:1, Informative)
1) The reflection off the lips is too bright
2) There's something wrong with the shadow of the nose
3) The tip of the nose is too reflective.. in fact all of the areas that are in direct light are too reflective
4) The proportions of the face are off slightly (or they are too perfect and symmetrical to be real)
5) It may be the render resolution, but the imperfections of the cheek are too lumpy
But it is a heck of a lot better than a couple of years ago.
Re:You know you're a geek (Score:2, Informative)
So, your pr0n goddess would be fat as well as large breasted. In propper digital pr0n she'd be:
Bust: 36ZZZ
Waist: 17
Hips: 35
With no gag reflex and an abdominal cavity with the storage capacity of an oil tanker.
past perfect (Score:3, Informative)
BTW, literally "perfect" skin would mostly resemble Campbell's Cream of Bean soup.
Re:Old news... (Score:2, Informative)
that photo is old.... (Score:2, Informative)
Realistic != perfect (Score:2, Informative)
Re:Forget DOOM 3! (Score:2, Informative)
Re:Open Source Projects? (Score:2, Informative)
BTW, here's the technique. It's really simple actually:
Before rendering each frame:
- sample the object with points on its surface;
- solve the illumination of each sample point (to get the amount of light falling on each)
- save this data somewhere.
During rendering:
- For every point being rendered, look for nearby samples (several techniques could be used for this, the paper used an octree structure, but my first implementation used just a flat 3d bucket sort of the samples)
- Average the values of all nearby samples, with some kind of falloff (the paper does the right physical think, using an exponential function--my first implementation used a cubic function that approximated the exponential while falling off to zero at a finite distance)
The value you get approximates the amount of scattered light. That's all there is to our 2002 paper, really. The rest is math, justification and embellishments. There is a lot more to rendering skin than subsurface scattering though, like layering and good texture maps, plus usability if you have tens of artists using the tools.
And yes, the technique could be patented, but it would very much suck if we had done that. My implementation is closed, since I wrote it at PDI on our propietary renderer, but as you see, it's simple to implement anyway.
Juan Buhler
(coauthored Henrik's 2002 paper)