Final Presentation Extension to GPU based path tracer

Final Presentation Extension to GPU based path tracer By- Gundeep Singh

Extended my path tracer • Features added-: a) Obj Mesh Loader b) Subsurface scattering c) Cook Torrance BRDF d) Fresnel reflection e) Interactive Camera f) Depth of field g) Motion Blur h) Post processing effects for fun!

Mesh loader • Implemented a Obj Mesh Loader to handle arbitrary geometry.

Interactive camera • Controls to move within the scene. • The path tracer is reset after every camera movement.

Subsurface scattering • Subsurface scattering(or SSS) is a mechanism of light transport in which light penetrates the surface of a translucent object, is scattered by interacting with the material, and exits the surface at a different point. • To mimic effects of materials like milk, wax etc. i xi xo s o

Subsurface Scattering Bunny- 1100+ faces Reduction Coefficient= 2. 0

Depth of field • Earlier we are using pinhole camera now to implement depth of field we assume some size of camera. • Simple and most important concept for DOF is to jitter the location of ray start (i. e camera position) and construct a ray using that camera position.

Motion blur • Simply translating the objects between frames rest is taken care by the path tracer !

KD TREE • Was unable to complete implementing Cukd. • Needed some more time for that

Cook Torrance • What makes the Cook-Torrance shading model so favorable? o First, it computes its specular lobe using the half-angle vector o Second, it accurately models the Fresnel effect, increasing the specular reflectivity as the surface turns away from the viewing direction. o Finally, it models micro imperfections in the surface

Cook Torrance Results Roughness= 0. 2 Gauss Constant=100 Roughness= 0. 02 Gauss Constant= 50

Some post processing effects Contrast Gray Scale

References • Real time rendering book. • Pixar Cook Torrance http: //renderman. pixar. com/view/cooktorrance-shader • KD trees http: //graphics. stanford. edu/papers/gpu_kdtree/kdtree. pdf • Subsurface scattering http: //en. wikipedia. org/wiki/Subsurface_scattering • Depth of field http: //http. developer. nvidia. com/GPUGems/gpugems_ch 23. ht ml

Thank You