Ray/Path tracing examples
A sequence of images showing the
building up of features in a ray/path tracer to arrive at the
capabilities needed to produce this final image.
Ray Casting (1 ray per pixel)
| Display of simple lighting | Display of normals |
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| Display of distance along ray | Display of object/color |
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| Display glm::abs(rayDirection) | Display intersection with object's bounding-box |
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Path Tracing (implicit paths only); Diffuse BRDF
Scene file for diffuse images
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Paths are extended until they hit
a light or give up trying. Even with a light large close
in, most paths fail to find a light so the image starts
with lots of black pixels. Final image (right): 4096 passes; Others (below) at 1, 8, 64, and 512 passes. |
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Path Tracing (implicit and explicit paths); Diffuse BRDF
Scene file for diffuse images
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Each extension of the path is
accompanied by an explicit connection to a random point of
a random light. Convergence is much faster than the
previous implicit-only version. Final image (right): 4096 passes; Others (below) at 1, 8, 64, and 512 passes. |
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Path Tracing; Reflection BRDF
Scene file for reflection images
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The BRDF has been enhanced to
include specular reflection as well as the original
diffuse reflection. The sampling and Pdf have been chosen
to match. Final image (right): 4096 passes; |
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Path Tracing; Transmission BSDF
Scene file for transmission images
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The BSDF has been further enhanced
to include transmission through the surface, including
refraction according to Snell's law and light attenuation
according to Beer's law. Final image (right): 4096
passes; |
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Path Tracing with MIS weights
Scene file for diffuse images
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Multiple importance sampling (MIS)
factors in a weight to pre-converge values toward the
eventual average. Convergence is noticably faster for some
scenes that include shiny/refractive images. Final image (right): 4096 passes; Others (below) at 1, 8, 64, and 512 passes. |
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Path Tracing; Complex scene; Diffuse BRDF
Scene file for bvh test
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Scene contains 208383 objects,
mostly bunny triangles. Final image (right): 4096
passes; |
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Timing information for each sequence of images
All images are 400x300 pixels.
All measurements were taken on a 3.2Ghz quad processor.
All measurements were taken on a 3.2Ghz quad processor.
| Series | Total minutes | passes/second | minimumOnObject average calls per ray |
minimumOnVolume average calls per ray |
|---|---|---|---|---|
| Implicit | 20.4 | 3.35 | 8.97 | 20.41 |
| Implicit+Explicit | 35.7 | 1.91 | 8.91 | 20.26 |
| Implicit+Explicit+MIS | 36.3 | 1.88 | 8.91 | 20.26 |
| Reflection | 37.9 | 1.80 | 9.01 | 20.43 |
| Transmission | 40.0 | 1.71 | 9.26 | 21.33 |
| Complex scene | 122.9 | 0.56 | 8.10 | 114.12 |