Gallery of Computer Graphics at IMM


This page contains images and brief descriptions of computer graphcis projects that have been carried out by students, Ph.D. students and alumni from the department. Except where noted, the projects have been supervised by associate professor Niels Jørgen Christensen njc@imm.dtu.dk.
Topics
Global Illumination The Hybris Renderer Modelling in MAYA Virtual Reality Real-Time Hardware-Based Photorealistic Rendering Real-Time Soft Shadows Virticle (Distributed vehicle simulation) Volume Graphics

Global Illumination
Henrik Wann Jensen

Henrik Wann Jensen was a Ph.D. student back in the days when computer graphics belonged to the section of Graphical Communication. Both during his Ph.D. study and afterwards (as a post doc. at MIT and Stanford) he has produced amazing imagery using stochastic ray tracing in conjunction with the photon map technique. Since these images are from the Ph.D. period, they are not really representative of his current work. (Hit `learn more').

This is a glass of cognac on a sand-surface. The sand-surface is a fractal surface approximated by 2 million triangles on which a sand texture has been created. Notice the caustic on the sand. Notice also that the reflection model for the sand is directional diffuse - this image demonstrates how photon maps can render caustics on non Lambertian surfaces.

The museum image was rendered using the photon map based two-pass global illumination method. It took 45 minutes to render on a 100Mhz Pentium.

The Hybris Renderer
Hans Holten-Lund and Henrik A. Sørensen

The architectural design of the Hybris renderer is part of Hans Holten Lund's thesis work. The FPGA implementation discussed below is the subject of Henrik A. Sørensen's master's thesis. Both projects are supervised by associate professor Steen Pedersen.

Image showing the Stanford "Dragon" laserscan rendered using the FPGA hardware implementation of the tile-based Hybris rendering architecture. The object contains 870k triangles and was rendered in 2 seconds on an experimental Xilinx FPGA board running at 25 MHz.

Image showing the Stanford "Bunny" laserscan rendered using the FPGA hardware implementation of the tile-based Hybris rendering architecture. The rendering demonstrates dynamic mixing of point and triangle primitives, using the existing partitioning of the object. Small points were chosen for clarity.

The Center for Computational Research, University at Buffalo
Modelling in Maya by Bendik Stang

Image showing a VR model of the office at the Center for Computational Research at the University at Buffalo. The entire scene was meassured with ruler and modelled using MAYA 3.0 - Alias|Wavefront. The modelling was carried out during a stay at the University at Buffalo.

Virtual Reality
Bent Dalgaard Larsen

Bent Dalgaard Larsen is a Ph.D. student working on creating realistic and interactive virtual environments. Bent is interested in bringing global illumination to virtual reality, physics engines for VR, and highly dynamic environments. Finally, Bent is interested in making virtual environments accessible from low end and highly portable platforms.

This is a screenshot of the FLTK based desktop client allowing collaborative building of brick models. The interface is built in OpenGL using shadow volumes to create the shadows. Several people may collaborate on simultaneously building the model.

One of Bent's recent projects has been to create a cell phone client for his virtual environment. This cell phone interface allows cheap, pocketable (albeit limited) access to virtual environments on the upcoming generation of cell phones. The cell phone interface was presented as a sketch at SIGGRAPH 2002.

Real-Time Hardware-Based Photorealistic Rendering
Kasper Høy Nielsen

Kasper Høy Nielsen has recently completed his master's thesis. The work presented below is from Kasper's thesis with the title above.

Recursive curved and planar specular reflections using environment mapping and planar texture-based reflection mapping, combined with (pre-calculated) diffuse illumination stored as radiosity-textures. Glossy reflections (floor) are simulated using texture filtering. " Dynamic scene runs at approximately 10 fps on a GeForce 256.

Image shows multiple recursive (3rd order) planar and curved image-based interreflections. "infinite" recursive curved reflections (spheres) are simulated using view-independent environment mapping. Real-time performance: ~20 fps for static scene on a GeForce 256.

Recursive curved and planar specular reflections using environment mapping and planar texture-based reflection mapping, combined with diffuse illumination stored as radiosity-textures. Lighting conditions can be changed in real-time. Performance using 1st order reflections and vertex arrays: ~18 fps on a GeForce 256.

Real-Time Soft Shadows
Bjarke Jakobsen og Kim Steen Petersen

Kim and Bjarke have completed a real-time rendering project. Their main goal was to create a fast technique for soft shadows. They have come up with a new approach that is neither based on shadow volumes nor depth maps, although (vastly simplified) it can be seen as a combination.
The examples below show two of the most difficult scenes that the method has been applied to, and the rendering speed is below 20 fps on a Geforce3. However, normal speeds are in the neighbourhood of 40 to 70 fps.

One of the major challenges was to handle complex occluders. The image on the right shows two objects casting shadows. One of them (the mesh polyhedron) is such a complex occluder.
This scene renders at 13.6 fps. The limiting factor is the terrain.

This image shows soft shadows in combination with fog rendering. The fog was rendered using a billboarding technique also developed as part of Kim and Bjarke's project.
This scene becomes fill limited (due to the fog) and renders at 18 fps.

Virticle
Hans Palbøl

Virticle is a vehicle simulator that Hans Palbøl has recently implemented in the course of his master's project. The simulator is a cross-platform environment for vehicle simulation that uses SGI's OpenGL Performer for visualization.

The image on the right shows a shot of the vehicle in the simulation environment. The car is an inexepensive Fiesta in the interest of realism. Hans modelled the geometry of the car by hand, and applied textures from photos of the car.

Here, we've made it hard to overlook the bumper sticker.

Volume Graphics
J. Andreas Bærentzen

Andreas' Ph.D. project was about Volume Graphics in general and volume sculpting in particular. There are more images in the Volume Graphics Gallery . You may also be interested in the examples of texture based volume visualization shown here

The image on the right and on the right below are point rendered volumetric models. These are frames from Andreas' interactive sculpting system. The sculpting system employs volume manipulation operations are based on the CSG paradigm.

A notable feature of these CSG operations is that certain morphological constraints are enforced. Put plainly, the CSG operations encompass blending to avoid sharp edges. The image on the right shows the swinish result of a volumetric "cut and paste" operation.

This image is a picture of a model created with one of Andreas' older sculpting systems. The model was polygonized and rendered using PovRay.

Maintained by: Andreas Bærentzen, jab 'at' imm.dtu.dk
Last modified: Mon Aug 25 17:23:17 CEST 2003

Global Illumination Henrik Wann Jensen
Henrik Wann Jensen was a Ph.D. student back in the days when computer graphics belonged to the section of Graphical Communication. Both during his Ph.D. study and afterwards (as a post doc. at MIT and Stanford) he has produced amazing imagery using stochastic ray tracing in conjunction with the photon map technique. Since these images are from the Ph.D. period, they are not really representative of his current work. (Hit `learn more').
This is a glass of cognac on a sand-surface. The sand-surface is a fractal surface approximated by 2 million triangles on which a sand texture has been created. Notice the caustic on the sand. Notice also that the reflection model for the sand is directional diffuse - this image demonstrates how photon maps can render caustics on non Lambertian surfaces.
The museum image was rendered using the photon map based two-pass global illumination method. It took 45 minutes to render on a 100Mhz Pentium.

The Hybris Renderer Hans Holten-Lund and Henrik A. Sørensen
The architectural design of the Hybris renderer is part of Hans Holten Lund's thesis work. The FPGA implementation discussed below is the subject of Henrik A. Sørensen's master's thesis. Both projects are supervised by associate professor Steen Pedersen.
Image showing the Stanford "Dragon" laserscan rendered using the FPGA hardware implementation of the tile-based Hybris rendering architecture. The object contains 870k triangles and was rendered in 2 seconds on an experimental Xilinx FPGA board running at 25 MHz.
Image showing the Stanford "Bunny" laserscan rendered using the FPGA hardware implementation of the tile-based Hybris rendering architecture. The rendering demonstrates dynamic mixing of point and triangle primitives, using the existing partitioning of the object. Small points were chosen for clarity.

The Center for Computational Research, University at Buffalo Modelling in Maya by Bendik Stang
Image showing a VR model of the office at the Center for Computational Research at the University at Buffalo. The entire scene was meassured with ruler and modelled using MAYA 3.0 - Alias\|Wavefront. The modelling was carried out during a stay at the University at Buffalo.

Virtual Reality Bent Dalgaard Larsen
Bent Dalgaard Larsen is a Ph.D. student working on creating realistic and interactive virtual environments. Bent is interested in bringing global illumination to virtual reality, physics engines for VR, and highly dynamic environments. Finally, Bent is interested in making virtual environments accessible from low end and highly portable platforms.
This is a screenshot of the FLTK based desktop client allowing collaborative building of brick models. The interface is built in OpenGL using shadow volumes to create the shadows. Several people may collaborate on simultaneously building the model.
One of Bent's recent projects has been to create a cell phone client for his virtual environment. This cell phone interface allows cheap, pocketable (albeit limited) access to virtual environments on the upcoming generation of cell phones. The cell phone interface was presented as a sketch at SIGGRAPH 2002.

Real-Time Hardware-Based Photorealistic Rendering Kasper Høy Nielsen
Kasper Høy Nielsen has recently completed his master's thesis. The work presented below is from Kasper's thesis with the title above.
Recursive curved and planar specular reflections using environment mapping and planar texture-based reflection mapping, combined with (pre-calculated) diffuse illumination stored as radiosity-textures. Glossy reflections (floor) are simulated using texture filtering. " Dynamic scene runs at approximately 10 fps on a GeForce 256.
Image shows multiple recursive (3rd order) planar and curved image-based interreflections. "infinite" recursive curved reflections (spheres) are simulated using view-independent environment mapping. Real-time performance: ~20 fps for static scene on a GeForce 256.
Recursive curved and planar specular reflections using environment mapping and planar texture-based reflection mapping, combined with diffuse illumination stored as radiosity-textures. Lighting conditions can be changed in real-time. Performance using 1st order reflections and vertex arrays: ~18 fps on a GeForce 256.

Real-Time Soft Shadows Bjarke Jakobsen og Kim Steen Petersen
Kim and Bjarke have completed a real-time rendering project. Their main goal was to create a fast technique for soft shadows. They have come up with a new approach that is neither based on shadow volumes nor depth maps, although (vastly simplified) it can be seen as a combination. The examples below show two of the most difficult scenes that the method has been applied to, and the rendering speed is below 20 fps on a Geforce3. However, normal speeds are in the neighbourhood of 40 to 70 fps.
One of the major challenges was to handle complex occluders. The image on the right shows two objects casting shadows. One of them (the mesh polyhedron) is such a complex occluder. This scene renders at 13.6 fps. The limiting factor is the terrain.
This image shows soft shadows in combination with fog rendering. The fog was rendered using a billboarding technique also developed as part of Kim and Bjarke's project. This scene becomes fill limited (due to the fog) and renders at 18 fps.

Virticle Hans Palbøl
Virticle is a vehicle simulator that Hans Palbøl has recently implemented in the course of his master's project. The simulator is a cross-platform environment for vehicle simulation that uses SGI's OpenGL Performer for visualization.
The image on the right shows a shot of the vehicle in the simulation environment. The car is an inexepensive Fiesta in the interest of realism. Hans modelled the geometry of the car by hand, and applied textures from photos of the car.
Here, we've made it hard to overlook the bumper sticker.

Volume Graphics J. Andreas Bærentzen
Andreas' Ph.D. project was about Volume Graphics in general and volume sculpting in particular. There are more images in the Volume Graphics Gallery . You may also be interested in the examples of texture based volume visualization shown here
The image on the right and on the right below are point rendered volumetric models. These are frames from Andreas' interactive sculpting system. The sculpting system employs volume manipulation operations are based on the CSG paradigm.
A notable feature of these CSG operations is that certain morphological constraints are enforced. Put plainly, the CSG operations encompass blending to avoid sharp edges. The image on the right shows the swinish result of a volumetric "cut and paste" operation.
This image is a picture of a model created with one of Andreas' older sculpting systems. The model was polygonized and rendered using PovRay.