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Re: My first Supersize-Image

Posted: Fri May 03, 2019 3:45 am
by XMAMan
Ok here is my first little step to subsurface scattering. I have extended my bidirectional pathtracing with Homogen-Media-Support. So I have now a unbiased estimator. The next steps will be Rayleigh,Mie-Scattering and inhomogeneous media.

Re: My first Supersize-Image

Posted: Sat Jun 15, 2019 8:39 pm
by XMAMan
Step 2: Rayleigh- and Mie-Scattering.

For Rayleigh-Phase-Function-Direction-Sampling I used 'Importance sampling the Rayleigh phase function from jeppe' (Inverse CDF)
For the Mie I use tabulation and the formula from 'ScratchAPixel Simulating the Colors of the Sky'

For distancesamling, I use Raab-Woodcock 'Unbiased Global Illumination with Participating Media - Raab et al (2008)'.

For the attenuation-term I use a pre-computed table. A little Idea how to implement I used the paper from Nishita 'Display Method of the Sky Color Taking into Account Multiple Scattering 1996'.

The next step is adding clouds.

Re: My first Supersize-Image

Posted: Mon Jun 24, 2019 3:56 am
by XMAMan
In the next Image you can see the difference between single-scattering and multiple-scattering
Image 1: Bidirectional Pathtracing (MultipeScattering)
Image 2: Sampling a Particle-Point on the Edge from a Eye-Subpaht (Dont know the offizial name from this path-creation-sampling-routine) (MultipeScattering)
Image 3: Sampline a Particle-Point only on the edge from the Primary-Ray (Single Scattering)
Image 4: Create 20 Segments on the Primary-Ray-Edge and connect it to the sun (Single Scattering)