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Project Raytracing

Project Raytracing. Content. Goals Idea of Raytracing Ray Casting Therory Practice Raytracing Theory Light model Practice Output images Conclusion. Specifications. Ray tracer depends on how to represent objects Parametric equation for precision, not rapidity

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Project Raytracing

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  1. Project Raytracing

  2. Content • Goals • Idea of Raytracing • Ray Casting • Therory • Practice • Raytracing • Theory • Light model • Practice • Output images • Conclusion

  3. Specifications Ray tracer depends on how to represent objects Parametric equation for precision, not rapidity Develop a Ray Tracer in order to explore a new intersection algorithm Two teams : - for mathematics - for code

  4. Main principle Create 3D pictures Mathematical equation Throw ray from eye to pixels Not FROM source light: TO it Number of reflections Great pictures but slow

  5. Algorithms Ray casting - first method - no bounce Ray tracing - from eye to pixels - reflection - refraction - shadow

  6. Fields of use Animation studio Pixar: with parsimony → light effects Video games → with triangles → faster and great

  7. Ray casting For each pixel: • Shoot a ray from the observer to the position of the pixel • Test if the ray hits an object in the scene • If thereis a hit: the color of this pixel willbe the color of the object • If thereis no hit: the pixel receives the color of the background

  8. Ray casting What do weneed ? • A position for the observer (eye, camera) • A direction/object to look at (and a « way up ») • An object to show on screen • A representation of the 2D screen in the 3D space

  9. Ray casting

  10. Our Ray Caster

  11. From Ray Casting to Ray Tracing

  12. From Ray Casting to Ray Tracing Weadd : • Lights ambient, diffuse, specular • Shadows • Reflexion => recursion : another ray isshotfrom the intersection • Materialproperties ambient, diffuse, and specular coefficients

  13. Lightmodel • Used: Phong reflection model • 3 types of light: ambient, diffuse, specular =

  14. Ambient and Diffuse The coefficient is specific for a material

  15. Specular

  16. Shadows • Only add diffuse and specular light, if a lightsource is visible • Test for intersections between a point on the sphere and the lightsource

  17. From Ray Casting to Ray Tracing Weadd : • Lights ambient, diffuse, specular • Shadows • Reflexion => recursion : another ray isshotfrom the intersection • Materialproperties ambient, diffuse, and specular coefficients

  18. Videolink 1

  19. Videolink 2

  20. Interesting modules • Positionning of the screen in 3D space • The RayTracer class • That's the core of the program (light model) • Shadows • The use of inheritance to compute intersections • Obtaining an animation • Camera and lights movement • Export a sequence of images, make a movie • The Draughtboard

  21. Difficulties - math libraries - C++, compilation, building environment - Screen implementation - Unexpected results (debugging)

  22. Achievements Light effects Animation rendering Different shapes Antialiasing

  23. Improvements Refraction and transparency Textures and noise Depth of Field Image mapping Bounding Volume Radiometry (power, energy, radiance...) Photon mapping

  24. Thanks! Thank you for your attention!

  25. Questions?

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