Relief Clipping Planes SIGGRAPH ASIA 2008

Slide 1: 

:: :: :: Relief Clipping Planes For Real-Time Rendering :: Matthias Trapp :: :: 1

Slide 2: 

:: :: :: Relief Clipping Planes For Real-Time Rendering :: Matthias Trapp :: :: 2 Matthias Trapp, Jürgen DöllnerHasso-Plattner-Institute, University of Potsdam, Germany Relief Clipping PlanesFor Real-Time Rendering

Results : 

:: :: :: Relief Clipping Planes For Real-Time Rendering :: Matthias Trapp :: :: 3 Results

Motivation : 

:: :: :: Relief Clipping Planes For Real-Time Rendering :: Matthias Trapp :: :: 4 Motivation Relief Clipping Planes (RCP): Create more sophisticated cut-away views Enables non-regular cut-surfaces Contributions: New clip plane parameterization Automatic cap-surface generation Implementation Goals: Interactive configuration Use hardware acceleration

Relief Clip-Plane Parameterization : 

:: :: :: Relief Clipping Planes For Real-Time Rendering :: Matthias Trapp :: :: 5 Relief Clip-Plane Parameterization O Plane Origin U, V Direction Vectors S = (sx,sy,sz) Scaling Vector OM Offsetmap

Clipping Equation : 

:: :: :: Relief Clipping Planes For Real-Time Rendering :: Matthias Trapp :: :: 6 Clipping Equation

GLSL Fragment-Shader Source : 

:: :: :: Relief Clipping Planes For Real-Time Rendering :: Matthias Trapp :: :: 7 GLSL Fragment-Shader Source

Multiple Clipping Planes : 

:: :: :: Relief Clipping Planes For Real-Time Rendering :: Matthias Trapp :: :: 8 Multiple Clipping Planes

Capping Openings – The Goal… : 

:: :: :: Relief Clipping Planes For Real-Time Rendering :: Matthias Trapp :: :: 9 Capping Openings – The Goal… http://www.bmbikes.co.uk/photos/museumphotos/Broken 20R60-6 Crank.jpg Assumption: Input Mesh is SOLID.

Capping – The Process : 

:: :: :: Relief Clipping Planes For Real-Time Rendering :: Matthias Trapp :: :: 10 Capping – The Process Goals: Convey material / inner structure of the input solid Enable assisted modeling of cap-surface appearance Solution: Polygonal Cap-Surface Directly derived from relief-clipping plane Rendering after the clipping pass

Generating the Cap-Surface : 

:: :: :: Relief Clipping Planes For Real-Time Rendering :: Matthias Trapp :: :: 11 Generating the Cap-Surface Phase A: Dynamic Mesh Refinement on GPU [Boubekeur05] Perform displacement, shading, texturing,… Phase B: Clip away “outside” parts of the cap-surface

Decision Problem : 

:: :: :: Relief Clipping Planes For Real-Time Rendering :: Matthias Trapp :: :: 12 Decision Problem Which point P of the cap-surface is inside a solid S ? Solution: Volumetric depth test Needed: Additional data structure Layered Depth Image (LDI) [Shade98] Image-based representation of shape Computed in pre-processing [Everitt01]

Example of Layered Depth Image : 

:: :: :: Relief Clipping Planes For Real-Time Rendering :: Matthias Trapp :: :: 13 Example of Layered Depth Image

Volumetric Depth Test : 

:: :: :: Relief Clipping Planes For Real-Time Rendering :: Matthias Trapp :: :: 14 Volumetric Depth Test [Trapp08]

Conclusions : 

:: :: :: Relief Clipping Planes For Real-Time Rendering :: Matthias Trapp :: :: 15 Conclusions Summary Advanced clipping approach Real-time rendering technique Fully implemented on GPU Drawbacks Needs additional data structure Needs high-tessellated cap-surface Future Work Generalized approach for clipping

Thank You ! - Questions ? : 

:: :: :: Relief Clipping Planes For Real-Time Rendering :: Matthias Trapp :: :: 16 Thank You ! - Questions ? Contact: Matthias Trapp matthias.trapp@hpi.uni.potsdam.de Jürgen Döllner juergen.doellner@hpi.uni.potsdam.de Computer Graphics Systems Group http://www.hpi.uni-potsdam.de/doellner/