Real-Time Rendering of Rough Refraction

We present an algorithm to render objects made of transparent materials with rough surfaces in real-time, under all-frequency distant illumination. Rough surfaces cause wide scattering as light enters and exits objects, which significantly complicates the rendering of such materials. We present two contributions to approximate the successive scattering events at interfaces, due to rough refraction: First, an approximation of the Bidirectional Transmittance Distribution Function (BTDF), using spherical Gaussians, suitable for real-time estimation of environment lighting using preconvolution; second, a combination of cone tracing and macrogeometry filtering to efficiently integrate the scattered rays at the exiting interface of the object. We demonstrate the quality of our approximation by comparison against stochastic ray tracing. Furthermore we propose two extensions to our method for supporting spatially varying roughness on object surfaces and local lighting for thin objects.

[1]  Michael Toksvig.  Mipmapping Normal Maps , 2005, J. Graph. Tools.

[2]  Hans-Peter Seidel,et al.  Light Field Techniques for Reflections and Refractions , 1999, Rendering Techniques.

[3]  Elmar Eisemann,et al.  Fast scene voxelization and applications , 2006, I3D '06.

[4]  Steve Marschner,et al.  Microfacet Models for Refraction through Rough Surfaces , 2007, Rendering Techniques.

[5]  Baining Guo,et al.  The Dual‐microfacet Model for Capturing Thin Transparent Slabs , 2009, Comput. Graph. Forum.

[6]  Erik Reinhard,et al.  Image-based material editing , 2005, SIGGRAPH '05.

[7]  Hans-Peter Seidel,et al.  Unified Approach to Prefiltered Environment Maps , 2000, Rendering Techniques.

[8]  John Amanatides,et al.  Ray tracing with cones , 1984, SIGGRAPH.

[9]  David A. Forsyth,et al.  Generalizing motion edits with Gaussian processes , 2009, ACM Trans. Graph..

[10]  Shi-Min Hu,et al.  Popup: automatic paper architectures from 3D models , 2010, SIGGRAPH 2010.

[11]  Manuel Menezes de Oliveira Neto,et al.  Real-time refraction through deformable objects , 2007, SI3D.

[12]  Adrien Bousseau,et al.  Real-time rough refraction , 2011, SI3D.

[13]  Michael S. Brown,et al.  Matting and compositing of transparent and refractive objects , 2011, TOGS.

[14]  H. Seidel,et al.  Pattern-aware Deformation Using Sliding Dockers , 2011, SIGGRAPH 2011.

[15]  Kun Zhou,et al.  Interactive Rendering of Non‐Constant, Refractive Media Using the Ray Equations of Gradient‐Index Optics , 2010, Comput. Graph. Forum.

[16]  Kun Zhou,et al.  Interactive relighting of dynamic refractive objects , 2008, ACM Trans. Graph..

[17]  Hans-Peter Seidel,et al.  Eikonal rendering: efficient light transport in refractive objects , 2007, SIGGRAPH '07.

[18]  Pat Hanrahan,et al.  A signal-processing framework for inverse rendering , 2001, SIGGRAPH.

[19]  David K. McAllister,et al.  OptiX: a general purpose ray tracing engine , 2010, ACM Trans. Graph..

[20]  Baining Guo,et al.  All-frequency rendering of dynamic, spatially-varying reflectance , 2009, ACM Trans. Graph..

[21]  R. Ramamoorthi,et al.  Frequency domain normal map filtering , 2007, SIGGRAPH 2007.

[22]  Roland W Fleming,et al.  Real-world illumination and the perception of surface reflectance properties. , 2003, Journal of vision.

[23]  David J. Fleet,et al.  Optimizing walking controllers , 2009, SIGGRAPH 2009.

[24]  James F. Blinn,et al.  Models of light reflection for computer synthesized pictures , 1977, SIGGRAPH.

[25]  Chris Wyman.  An approximate image-space approach for interactive refraction , 2005, ACM Trans. Graph..

[26]  Pat Hanrahan,et al.  Frequency space environment map rendering , 2002, SIGGRAPH.