László Szirmay-Kalos Budapesti University of Technology and Economics Department of Control Engineering and Information Technology and Graphisoft R&D Photorealistic Image Synthesis in CAD Systems (IKTA /2000 )

Photorealistic Image Synthesis in CAD systems2 The Project A research project between BUTE and Graphisoft Research topic: global illumination in architectural CAD systems January 2001 – April 2002 Homepage: Participants: –Project leader: dr. László Szirmay-Kalos ( BUTE ) –Advisors: dr. László Szirmay-Kalos ( BUTE ) and László Sparing (Graphisoft) –PhD students: György Antal, Ferenc Csonka (Graphisoft), László Kovács ( BUTE ), Benedek Balazs ( BUTE ), Szécsi László ( BUTE ) –Others: dr. Horváth Tamás ( BUTE ), Csaba Kelemen The main results: scientific research and a new framework called RenderX for testing and implementing global illumination algorithms

Photorealistic Image Synthesis in CAD systems3 Graphisoft and ArchiCAD Graphisoft was promoted in 1982 It is the third software company in the AEC sector ( Architecture, Engineering and Construction ) The leading product of Graphisoft is the ArchiCAD, which is an object oriented, 3D design software for the architecture and building industry

Photorealistic Image Synthesis in CAD systems4 Outlines Objective of the project Photorealistics image synthesis fundamentals The result of the project Products and applications

Photorealistic Image Synthesis in CAD systems5 Goal of the project Global illumination image synthesis –Must be physically accurate –Solving the rendering equation –Identify all potential light paths –Conventional methods took hours to render Interactive naviagation and animation –must produce new images in seconds

Photorealistic Image Synthesis in CAD systems6 The aim of image synthesis In the virtual world, a virtual camera makes the photo of the scene. The camera looks into the world through a window The camera sees the scene like this

Photorealistic Image Synthesis in CAD systems7 The rendering equation L= L e + T L

Photorealistic Image Synthesis in CAD systems8 How does the Nature work? 100 W light bulb emits photon per second The calculation of the intersected patches, that the photons hit is determined parallel with the speed of light The photons are absorbed randomly or reflected into a random direction Very little fraction of the emitted photons arrive finally to the eye

Photorealistic Image Synthesis in CAD systems9 Local Illumination Top: sharp (left) and soft (right) shadows on local illumination images Down: the global illumination image (H. W. Jensen, 1996)

Photorealistic Image Synthesis in CAD systems10 Global Illumination Identify all the possible light paths via multiple reflections, from the light source to the eye

Photorealistic Image Synthesis in CAD systems11 Global Illumination Follow the light paths from the camera to the eye with another method (Szirmay-Kalos László, 2000)

Photorealistic Image Synthesis in CAD systems12 Results Publications in 2001: –László Szirmay-Kalos, Ferenc Csonka, György Antal: Global Illumination as a Combination of Continuous Random Walk and Finite Element Based Iteration, Eurographics Conference, 2001 –Csaba Kelemen, László Szirmay-Kalos: A Microfacet Based Coupled Specular-Matte BRDF Model with Importance Sampling, Eurographics Conference, 2001 –Csaba Kelemen, László Szirmay-Kalos: Simple and Robust Mutation Strategy for Metropolis Light Transport Algorithm, Dagstuhl Seminar on Monte-Carlo Methods in Rendering, 2001 –György Antal, László Szirmay-Kalos, Ferenc Csonka, Csaba Kelemen: Multiple Strategy Stochastic Iteration for Architectural Walkthroughs, Dagstuhl Seminar on Monte-Carlo Methods in Rendering, 2001 –Ferenc Csonka, László Szirmay-Kalos György Antal: Cost-Driven Multiple Importance Sampling for Monte-Carlo Rendering, MCM Conference, Salzburg, 2001 –György Antal, László Szirmay-Kalos, Ferenc Csonka, Csaba Kelemen: Multiple Strategy Stochastic Iteration for Architectural Walkthroughs, Technical Report, TR , Vienna, 2001 –Csaba Kelemen, László Szirmay-Kalos: Simple and Robust Mutation Strategy for Metropolis Light Transport Algorithm, Technical Report, TR , Vienna, 2001 –Ferenc Csonka, László Szirmay-Kalos György Antal: Cost-Driven Multiple Importance Sampling for Monte-Carlo Rendering, MCM Conference, Technical Report, TR , Vienna, 2001 –László Szirmay-Kalos, László Kovács, Ali Mohamed Abbas: Testing Global Illumination Methods with Analytically Computable Scenes Winter School of Computer Graphics Conf., 2001 –Roel Martínez, László Szirmay-Kalos, Mateu Sbert, Ali Mohamed Abbas: Parallel Implementation of Stochastic Iteration Algorithms, Winter School of Computer Graphics Conf., 2001 –László Szirmay-Kalos, György Antal, Mateu Sbert: Progressive Light Path Development, Winter School of Computer Graphics Conf., 2001

Photorealistic Image Synthesis in CAD systems13 Results Publications in 2002: –György Antal, László Szirmay-Kalos, Ferenc Csonka: Weighted Multipass Method Based on Stochastic Iteration and Random Walk Methods, Winter School Of Computer Graphics Conference, 2002 –Csaba Kelemen, László Szirmay-Kalos, György Antal, Ferenc Csonka: Simple and Robust Mutation Strategy for Metropolis Light Transport Algorithm, Eurographics Conference, 2002 –György Antal, László Szirmay-Kalos, Ferenc Csonka: Hemicube Shooting for Non-Diffuse Global Illumination, Spring Conference on Computer Graphics, 2002 –László Szirmay-Kalos, Vlastimil Havran, Balázs Benedek, László Szécsi: On the Efficiency of Ray-shooting Acceleration Schemes, Spring Conference on Computer Graphics, 2002 Submitted papers: –György Antal, László Szirmay-Kalos, Ferenc Csonka, Csaba Kelemen: Multiple Strategy Stochastic Iteration for Architectural Walkthroughs –Ferenc Csonka, László Szirmay-Kalos, György Antal: Cost-Driven Multiple Importance Sampling for Monte-Carlo Rendering –Ferenc Csonka, László Szirmay-Kalos, Csaba Kelemen, György Antal: Dependent Tests driven Filtering in Monte-Carlo Global Illumination –György Antal, Ferenc Csonka: An Efficient And Robust Framework for Global Illumination Algorithms, 1 st Hungarian Conference on Computer Graphics, 2002 –Ferenc Csonka, György Antal: A Multi-Phase Energy Preserving Filtering Method for Architectural Scenes, 1 st Hungarian Conference on Computer Graphics, 2002

Photorealistic Image Synthesis in CAD systems14 Applications The CAD programs connect to the global illumination application via 3D File formats: SCE, 3DS, VRML, MGF. Ray Bundle RenderX SCE 3DS, VRML, MGF,... SceWriterArchiCAD 3D Studio Maya

Photorealistic Image Synthesis in CAD systems15 RenderX SCE 3DS VRML MGF Wireframe Local Illumination Ray-Tracing Ray Bundles (Gouraud) Ray Bundles (Phong) Path Tracing Bidirectional Path Tracing Metropolis... Scaling Ward etc.

Photorealistic Image Synthesis in CAD systems16 Stochastic Iteration Finite element methods 15 K patches 5 seconds 12 20

Photorealistic Image Synthesis in CAD systems17 Stochastic Iteration with Phong shading

Photorealistic Image Synthesis in CAD systems18 Production quality Monte-Carlo methods

Photorealistic Image Synthesis in CAD systems19 Walkthrough Animation Place camera keyframes in ArchiCAD, save scene, calculate global illumination animation in RenderX