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Motivation and Objective Delta3D Rain Falling Effect Conclusion and Future work

Algorithms for Atmospheric Special Effects in Graphics and their Implementation

Pisith Hao

under Guidance of

• Prof. Sharat Chandran

Department of Computer Science and Engineering IIT Bombay

July 24, 2007

Pisith Hao under Guidance of Prof. Sharat Chandran Atmospheric Special Effects in Graphics

Motivation and Objective Delta3D Rain Falling Effect Conclusion and Future work

Outline

1

Motivation and Objective Motivation Objective

2

Delta3D What’s Delta3D? Why Delta3D?

3

Rain Falling Effect Using Delta3D Particle Editor Using Physical Properties-Based Method

4

Conclusion and Future work

Pisith Hao under Guidance of Prof. Sharat Chandran Atmospheric Special Effects in Graphics

Motivation and Objective Delta3D Rain Falling Effect Conclusion and Future work Motivation Objective

Outline

1

Motivation and Objective Motivation Objective

2

Delta3D What’s Delta3D? Why Delta3D?

3

Rain Falling Effect Using Delta3D Particle Editor Using Physical Properties-Based Method

4

Conclusion and Future work

Pisith Hao under Guidance of Prof. Sharat Chandran Atmospheric Special Effects in Graphics

Motivation and Objective Delta3D Rain Falling Effect Conclusion and Future work Motivation Objective

Motivation

The current graphics hardware’s computation speed is improving

Increase the possibility of simulating the complex environment especially atmospheric special effects High degree of atmospheric realism becomes more challenging

Atmospheric special effects such as rain, cloud, snow and

• ther outdoor scenes are important in creating realistic

environment in order to immerse user in a visually convincing environment.

Pisith Hao under Guidance of Prof. Sharat Chandran Atmospheric Special Effects in Graphics

Motivation and Objective Delta3D Rain Falling Effect Conclusion and Future work Motivation Objective

Outline

1

Motivation and Objective Motivation Objective

2

Delta3D What’s Delta3D? Why Delta3D?

3

Rain Falling Effect Using Delta3D Particle Editor Using Physical Properties-Based Method

4

Conclusion and Future work

Pisith Hao under Guidance of Prof. Sharat Chandran Atmospheric Special Effects in Graphics

Motivation and Objective Delta3D Rain Falling Effect Conclusion and Future work Motivation Objective

Objective

Rain is a very complex atmospheric physical phenomenon and consists of numerous effects :

Rain falling : light rain, moderate rain, heavy rain, and extreme rain Water puddles on the streets Splashing of raindrop Water rippling Falling raindrops dripping off object’s surfaces Water streaming off on streets and objects

Make algorithms of the above effects as many as possible and implement them on Delta3D Effects should be able to run in real time

Pisith Hao under Guidance of Prof. Sharat Chandran Atmospheric Special Effects in Graphics

Motivation and Objective Delta3D Rain Falling Effect Conclusion and Future work Motivation Objective

Objective

Objective of the project

Pisith Hao under Guidance of Prof. Sharat Chandran Atmospheric Special Effects in Graphics

Motivation and Objective Delta3D Rain Falling Effect Conclusion and Future work What’s Delta3D? Why Delta3D?

Outline

1

Motivation and Objective Motivation Objective

2

Delta3D What’s Delta3D? Why Delta3D?

3

Rain Falling Effect Using Delta3D Particle Editor Using Physical Properties-Based Method

4

Conclusion and Future work

Pisith Hao under Guidance of Prof. Sharat Chandran Atmospheric Special Effects in Graphics

Motivation and Objective Delta3D Rain Falling Effect Conclusion and Future work What’s Delta3D? Why Delta3D?

What’s Delta3D?

Open Source engine which can be used for game, simulations, or other graphical applications Cross-platform (Windows and Linux) Use the standard Lesser GNU Public License Its modular design integrates other well-known Open Source projects :

OpenSceneGraph: cross platform graphics toolkit Open Dynamics Engine: library for simulating rigid body dynamics Character Animation Library: skeletal animation based 3D character animation library OpenAL: cross-platform 3D audio API

Pisith Hao under Guidance of Prof. Sharat Chandran Atmospheric Special Effects in Graphics

Motivation and Objective Delta3D Rain Falling Effect Conclusion and Future work What’s Delta3D? Why Delta3D?

Outline

1

Motivation and Objective Motivation Objective

2

Delta3D What’s Delta3D? Why Delta3D?

3

Rain Falling Effect Using Delta3D Particle Editor Using Physical Properties-Based Method

4

Conclusion and Future work

Pisith Hao under Guidance of Prof. Sharat Chandran Atmospheric Special Effects in Graphics

Motivation and Objective Delta3D Rain Falling Effect Conclusion and Future work What’s Delta3D? Why Delta3D?

Why Delta3D?

Selected for implementation of our algorithms due to Delta3D : leverages the success of existing open source tool such as OpenSceneGraph contains an interesting particle system editor, which is allowed to use graphical tool to change the properties of a particle system and see the effects immediately in real time. is available in source code that can be modified to meet

• ur requirements (atmospheric special effects)

Hence, it’s really a good starting point for our project

Pisith Hao under Guidance of Prof. Sharat Chandran Atmospheric Special Effects in Graphics

Motivation and Objective Delta3D Rain Falling Effect Conclusion and Future work Using Delta3D Particle Editor Using Physical Properties-Based Method

Outline

1

Motivation and Objective Motivation Objective

2

Delta3D What’s Delta3D? Why Delta3D?

3

Rain Falling Effect Using Delta3D Particle Editor Using Physical Properties-Based Method

4

Conclusion and Future work

Pisith Hao under Guidance of Prof. Sharat Chandran Atmospheric Special Effects in Graphics

Motivation and Objective Delta3D Rain Falling Effect Conclusion and Future work Using Delta3D Particle Editor Using Physical Properties-Based Method

Using Delta3D Particle Editor (1/4)

1

Create a texture of a rain drop and mapped it on a small billboard (face to viewer)

2

Make a rectangular emitter to shoot randomly particles straight down from a particular height

3

Set particle properties :

life of drop (2sec) size of drop (.15m to .25m) various number of particles creation (150 to 200particles/s) initial velocity rang of drops (6m/s to 10m/s)

so that raindrops don’t fall at a regular rates, numbers, and

• patterns. But most people will notice a pattern after a while.

4

Create other emitters (layers) setting different numbers to emitter’s properties and making different raindrop textures.

Pisith Hao under Guidance of Prof. Sharat Chandran Atmospheric Special Effects in Graphics

Motivation and Objective Delta3D Rain Falling Effect Conclusion and Future work Using Delta3D Particle Editor Using Physical Properties-Based Method

Using Delta3D Particle Editor (2/4)

Whenever a raindrop hits the wet surface of flat area (surface of the water in pool), circular of ripple (water ring) will occurs. This effect can be made by this particle system editor in a similar manner. Map water ring texture to a particle Make a rectangular emitter to shoot randomly particles but the shooting velocity has to be set to zero in order to keep the particle from floating upwards. Set size of particle (or water ring) from .00m to .16m so that enlargement of water ring can be seen

Pisith Hao under Guidance of Prof. Sharat Chandran Atmospheric Special Effects in Graphics

Motivation and Objective Delta3D Rain Falling Effect Conclusion and Future work Using Delta3D Particle Editor Using Physical Properties-Based Method

Using Delta3D Particle Editor (3/4)

two raindrop textures two water ring textures

Pisith Hao under Guidance of Prof. Sharat Chandran Atmospheric Special Effects in Graphics

Motivation and Objective Delta3D Rain Falling Effect Conclusion and Future work Using Delta3D Particle Editor Using Physical Properties-Based Method

Using Delta3D Particle Editor (4/4)

Unexpected result when raindrops are viewed downward from a particular height

Pisith Hao under Guidance of Prof. Sharat Chandran Atmospheric Special Effects in Graphics

Motivation and Objective Delta3D Rain Falling Effect Conclusion and Future work Using Delta3D Particle Editor Using Physical Properties-Based Method

Outline

1

Motivation and Objective Motivation Objective

2

Delta3D What’s Delta3D? Why Delta3D?

3

Rain Falling Effect Using Delta3D Particle Editor Using Physical Properties-Based Method

4

Conclusion and Future work

Pisith Hao under Guidance of Prof. Sharat Chandran Atmospheric Special Effects in Graphics

Motivation and Objective Delta3D Rain Falling Effect Conclusion and Future work Using Delta3D Particle Editor Using Physical Properties-Based Method

Using Physical Properties-Based Method (1/4)

This method is based on physical properties (geometrical, dynamic and optical) of raindrops (like ellipsoid). (a)Compare shapes of raindrops of radii R = 1mm, 1.5mm, 2mm, 2.5mm, and 3mm. (b)0.5mm. (c)1. (d)3. (e)4.5. Illustrates directions of reflected/refracted ray in a raindrop (Law of reflection and Snell’s law)

Pisith Hao under Guidance of Prof. Sharat Chandran Atmospheric Special Effects in Graphics

Motivation and Objective Delta3D Rain Falling Effect Conclusion and Future work Using Delta3D Particle Editor Using Physical Properties-Based Method

Using Physical Properties-Based Method (2/4)

Capture an image of the background scene to a texture Map texture onto the raindrops according to optical laws (Only Snell’s law) Not use Reflection’s law since a raindrop appears rather small on the screen, and relection is visible only in a small part of each raindrop

Pisith Hao under Guidance of Prof. Sharat Chandran Atmospheric Special Effects in Graphics

Motivation and Objective Delta3D Rain Falling Effect Conclusion and Future work Using Delta3D Particle Editor Using Physical Properties-Based Method

Using Physical Properties-Based Method (3/4)

Figure shows the comparison of a water-drop Left: an image simulated with this concept Right: a photograph of a real rain drop

Pisith Hao under Guidance of Prof. Sharat Chandran Atmospheric Special Effects in Graphics

Motivation and Objective Delta3D Rain Falling Effect Conclusion and Future work Using Delta3D Particle Editor Using Physical Properties-Based Method

Using Physical Properties-Based Method (4/4)

Figure shows rain falling simulated using this method. It’s still lack realism : not see raindrops inside the biggest raindrop no caustic no collision detection and merging of raindrops

Pisith Hao under Guidance of Prof. Sharat Chandran Atmospheric Special Effects in Graphics

Motivation and Objective Delta3D Rain Falling Effect Conclusion and Future work

Conclusion and Future work

Creating rain falling using Delta3D’s particle editor and Physical Properties-Based Method present the basic concept of making special effects and ideas for future work. Stage2 Project: from step 1 to 5 and Stage3 Project: from step 6 to 9

• 1. Study source code of particle system editor
• 2. Improve the Physical Properties-Based Method
• 3. Implement that method on particle editor
• 4. Create rain falling effect: light rain, moderate rain, heavy rain, and

extreme rain

• 5. Create effect of water puddle on the streets
• 6. Create raindrop splashing effect
• 7. Create water rippling effect
• 8. Create effect of falling raindrops dripping of object’s surfaces
• 9. Create effect of water streaming of on the streets and objects

Pisith Hao under Guidance of Prof. Sharat Chandran Atmospheric Special Effects in Graphics

Motivation and Objective Delta3D Rain Falling Effect Conclusion and Future work

Future work

Starting date and number of week to achieve each step are detail in the time schedule table below : Second Stage Project Time Schedule Steps Starting Date Number of Week to Finish 1 July 26 2 weeks 2 August 9 2 weeks 3 August 23 5 weeks 4 September 27 3 weeks 5 October 18 8 weeks Total 20 weeks Rest 3 weeks (December, 13 2007 - January, 8 2008)

Pisith Hao under Guidance of Prof. Sharat Chandran Atmospheric Special Effects in Graphics

Motivation and Objective Delta3D Rain Falling Effect Conclusion and Future work

Future work

Third Stage Project Time Schedule Steps Starting Date Number of Week to Finish 6 January 17 4 weeks 7 February 15 4 weeks 8 March 13 5 weeks 9 April 17 6 weeks Total 19 weeks Rest 6 weeks (May, 29 2008 - July, 10 2008)

Pisith Hao under Guidance of Prof. Sharat Chandran Atmospheric Special Effects in Graphics

Motivation and Objective Delta3D Rain Falling Effect Conclusion and Future work

References

[1] Delta3D. www.delta3d.org, accessed, June 2007. Last viewed on July, 11 2007. [2] Open Scene Graph. http://www.openscenegraph.org/, accessed, June 2007. Last viewed on July, 11 2007. [3] Open Dynamics Engine. http://www.ode.org/, accessed, June

• 2007. Last viewed on July, 11 2007.

[4] 3D Character Animation Library. https://gna.org/projects/cal3d/, accessed, June 2007. Last viewed on July, 11 2007. [5] OpenAL,Cross-Platform 3D Audio. http://www.openal.org/, accessed, June 2007. Last viewed on July, 11 2007. [6] GNU Lesser General Public License. http://www.gnu.org/licenses/lgpl.html, accessed, June 2007. Last viewed on July, 11 2007. [7] Falling Rain Particle Effect. http://www.delta3d.org/filemgmt/visit.php?lid=80, accessed, June

• 2007. Last viewed on July, 11 2007.

Pisith Hao under Guidance of Prof. Sharat Chandran Atmospheric Special Effects in Graphics

Motivation and Objective Delta3D Rain Falling Effect Conclusion and Future work

References

Rudy Darken, Perry McDowell, and Erik Johnson. Projects in VR: the Delta3D open source game engine. Computer Graphics and Applications, IEEE, Vol.25, Iss.3, May-June 2005. Pierre Rousseau, Vincent Jolivet, Djamchid Ghazanfarpour Realistic real-time rain rendering. Computer and Graphics, Vol.30, Iss.4, 507-518, 2006. Oliver N. Ross Optical Remote Sensing of Rainfall Microstructures Freie Universität Berlin, Fachbereich Physik, Diplom Thesis, 134pp, 2000.

Pisith Hao under Guidance of Prof. Sharat Chandran Atmospheric Special Effects in Graphics

Appendix Demo Pisith Hao under Guidance of Prof. Sharat Chandran Atmospheric Special Effects in Graphics