AMD and Crystal Dynamics Use TressFX to bring GPU Compute to Hair Simulation
Subject: Graphics Cards | February 26, 2013 - 10:04 AM | Ryan Shrout
Tagged: amd, tressfx, lara croft, tomb raider, crystal dynamics
Last week we got an email from AMD teasing an upcoming technology called TressFX that had something to do with hair and something to do with graphics. It should come as no surprise today that AMD has announced that TressFX is a hair modeling technology that utilized DirectCompute for simulation. The proper rendering of hair has been a thorn in the side of game developers for decades now and it seems that with every generation of GPU released by either NVIDIA or AMD/ATI we would see a tech demo about how hair modeling "has been changed forever."
This time though, we are seeing the technology in a AAA gaming title.
TressFX Hair revolutionizes Lara Croft’s locks by using the DirectCompute programming language to unlock the massively-parallel processing capabilities of the Graphics Core Next architecture, enabling image quality previously restricted to pre-rendered images. Building on AMD’s previous work on Order Independent Transparency (OIT), this method makes use of Per-Pixel Linked-List (PPLL) data structures to manage rendering complexity and memory usage.
DirectCompute is additionally utilized to perform the real-time physics simulations for TressFX Hair. This physics system treats each strand of hair as a chain with dozens of links, permitting for forces like gravity, wind and movement of the head to move and curl Lara’s hair in a realistic fashion. Further, collision detection is performed to ensure that strands do not pass through one another, or other solid surfaces such as Lara’s head, clothing and body. Finally, hair styles are simulated by gradually pulling the strands back towards their original shape after they have moved in response to an external force.
It's a lot of technology for a little bit of rendering - but realistic hair presents a very unique problem and I am very interested to see this in action when Tomb Raider releases on March 5th.
I asked AMD a couple of questions including if this was going to be a technology that NVIDIA users would be missing out on. Their response? "We don't create features that lock out other vendors." That doesn't mean GTX 600-series card users will have access to this accelerated hair technology or that it will perform similarly if they do, but I'll take a look when I get my hands on the game.
We are hoping to get some video to go along with our screenshots as I think that will have a stronger impact. You can find more details on AMD's TressFX landing page.