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Introduction
Speakers:
— Jim Sanders, FX Director, Gearbox Software
— Kevin Newkirk, Technical Artist, NVIDIA
Welcome to the Borderlands!
What is Borderlands2?
Borderlands 2
— Released: September 18, 2012
Developed by: Gearbox Software
Published by: 2k Games
— Metacritic: 90/100 on PC
— Unreal Engine 3 (modified)
Borderlands 2 is an action role-playing first
person shooter.
X-Play’s Game of the Year
Best shooter, Best multiplayer game (Spike TV VGA’s)
GPU Accelerated Effects
Using UE3’s NVIDIA PhysX SDK
— GPU EFFECTS
Persistent mesh debris
Force fields
SPH Fluid Simulation
Cloth simulation
— Most were stock UDK simulations!
Minimal implementation
GPU Accelerated Effects
Overview
What will you get from this presentation?
— A look at created GPU accelerated effects in Borderlands 2
— Benefits of accelerating your effects
— Deep dive into methods of creation
— A look at effects available to UE3/UDK users today.
Contents
Benefits of PhysX
Particles
Cloth
Fluid
QA
What were our benefits? Why did we do this?
We have dynamic tearing of cloth, enough said!
This added a new dimension to our game, a new character.
Helped us reach a new level of immersion that is exciting but not
overwhelming
Opened us up to a new way of thinking, what else can we do with this tech!
Development How would we do this?
A look at early discussions
Memory and Performance
What impact would this have on our development style
Custom Engine Tech
Can PhysX support dynamically generated content i.e. a bazillion guns?
DEEP DIVE
Persistent Debris
Persistent Debris
Persistent Debris
— Advantages
Persistence of debris
Additional interaction with later game events
— Force fields!
Added weight to visual impact on player
— What must a designer take into account?
Persistent Debris
Persistent Debris
Must be properly lit!
Good Particles Bad Particles
Persistent Debris
Persistent Debris
— Collisions must work all the time or breaks immersion
— Triangle collision is a must
Cloth!
Cloth! Simulated Cloth
— Initial Solution (Vertex Animation)
Cloth!
Simulated Cloth
— Simulated
Cost to simulate
— Have to be more aware as you decorate your level
Interaction with game events
Looked better!
Tearing!
Cloth!
Simulated Cloth
— Tearing!
Cloth!
Authoring
— Increase resolution of existing assets
Cloth!
Authoring
— Add bones
— Weight vertices
Fluid – Goo – Blood Ohhh MYYY!
Fluid – Goo – Blood Ohhh MYYY!
— What did we do?
Simulation: Smooth Particle Hydrodynamics
Rendering: Based on GDC2010 Simon Green “Screen Space Fluid Simulation”
Fluid – Goo – Blood Ohhh MYYY!
— What did the simulation give us?
Collision with game environment
“Density” value for rendering
Pressure waves create realistic fluids
Highly parallelized in CUDA
— ~25k particles simulated
Fluid – Goo – Blood Ohhh MYYY!
— Screen spaced fluid rendering
Non-marching cube solution
Entirely in screen space (no meshes)
Only generates surface closest to camera
Fast!
Fluid – Goo – Blood Ohhh MYYY!
— Last seen: Alice 2
— What improvements have been made?
Fluid – Goo – Blood Ohhh MYYY!
— Multiple fluids per screen
Early UE3 tests
Fluid – Goo – Blood Ohhh MYYY!
— Multiple fluids per screen
Allowed us to do lots of different effects on screen!
— No appreciable cost per additional material
— Colors controllable by particle system
Common simulation allowed for fluid iteraction
— This helped “boundaries” between the various liquids
to maintain color
Worked best with more opaque fluids
— Improvements still needed for mixing translucent materials
Fluid – Goo – Blood Ohhh MYYY!
— Downsampling
Fluid was downsampled to improve overall performance
Fluid – Goo – Blood Ohhh MYYY!
— Downsampling
Fluid is rendered at ½ resolution, caused edge artifacts
Used FXAA to smooth edge aliasing, minimal cost
— Fast Approximate Anti-Aliasing (FXAA) algorithm created by Timothy Lottes @ NVIDIA
— Smooths pixels instead of geometry, perfect for our fluid technique!
Fluid – Goo – Blood Ohhh MYYY!
— FXAA to the rescue!
Fluid – Goo – Blood Ohhh MYYY!
— Production lessons
Allow everything to be controlled in the effects package
— Color, Size, blur, edge quality all controlled per effect
Fluid – Goo – Blood Ohhh MYYY!
— Production lessons
Density is key
— Modified color/sizing by fluid density
Fluid – Goo – Blood Ohhh MYYY!
— Production lessons
Sorting can be hard, watch out for level designers!
Fluid – Goo – Blood Ohhh MYYY!
— Blood: to simulate or not to simulate (YES SIMULATE!)
Allowed an interesting gameplay change
Easier to determine hits, visible blood trails, fun?
Pushes the boundaries of some ratings
Next step: leaving decals
Questions?
Wrapping Up Resources
—https://developer.nvidia.com
—https://devtalk.nvidia.com (forums)
Presentation References
— https://developer.nvidia.com/content/fluid-simulation-alice-madness-
returns
— http://developer.download.nvidia.com/presentations/2010/gdc/Direct3
D_Effects.pdfGDC Exhibit Booth: #1602
