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Can you help setting up an interior closure for refraction ?

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Nachricht 1 von 7
maxtarpini
613 Aufrufe, 6 Antworten

Can you help setting up an interior closure for refraction ?

I'm using the same AiClosureVolumeHenyeyGreenstein on both spheres. I input directly sigmas without any re-parameterization for the moment. Scattering properties are those of milk. The volume one (right) is working cool but the one where I'm using the build-in AiMicrofacetRefractionBSDF clearly is not.. I'm simply pluggin the volume closure into the bsdf function..

AtRGB absorption { 0.0011f, 0.0024f, 0.014f };
AtRGB scattering { 2.55f, 3.21f, 3.77f };
scattering *= scale;
absorption *= scale;

AtClosure volScatter = AiClosureVolumeHenyeyGreenstein(sg, absorption, scattering, AI_RGB_BLACK, 0.f);

rBRDF = AiMicrofacetRefractionBSDF(sg, refract_albedo, rmodel, sg->N, NULL, sEta, rough2x, rough2x, dispersion, useFresnel, volScatter);

closures.add(rBRDF);

I'd expect that the refractionBSDF acts like a surface boundary driving rays into the participating medium however the medium ain't looking 'volumetric' at all as you can see.. no matter what values I plug in.. it looks more like a simple ray attenuation. I was looking to have the sphere interior the same as the volume on the right as I'm using the same volume code for both.interiorclosure.png

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6 ANTWORTEN 6
Nachricht 2 von 7
maxtarpini
als Antwort auf: maxtarpini

No one here ? I was looking to have the same rig you have with the standard material transmission.

@alan.kingFCDLA  :zwinkerndes_Gesicht:

Nachricht 3 von 7
Stephen.Blair
als Antwort auf: maxtarpini

Sorry, but Alan is away.
I'll see if anyone else can answer...



// Stephen Blair
// Arnold Renderer Support
Nachricht 4 von 7
Stephen.Blair
als Antwort auf: Stephen.Blair

Try using the AiMicrofacetRefractionBSDF_private call. Yeah, I know, a _private suffix...that was done to get the call in to a release without breaking the API 
 


// Stephen Blair
// Arnold Renderer Support
Nachricht 5 von 7
maxtarpini
als Antwort auf: Stephen.Blair

Thanks Stephen but I already tried that.
I suspect that there's some reparameterization that you forgot to lift or document.
You should give a look at std mat code.

 

OOC: keep pushing watts on your bike man ! :leicht_lächelndes_Gesicht: I do almost every day.

Nachricht 6 von 7
alan.kingFCDLA
als Antwort auf: maxtarpini

Hi, the lack of volume scattering with those settings is certainly odd, as if it were disabled. You may have to up your GI_transmission_samples or set the object's "opaque" setting to "false".

Nachricht 7 von 7
maxtarpini
als Antwort auf: alan.kingFCDLA

Thanks Alan! it was the opaque flag or better I wasn't dealing properly with shadow rays and transparency in the shader (doing that internally so I can have 'true caustics' without having to explicitely deal with ray types as you removed practically that option by making the opaque flag 'smarter' ). Now let's see if I'm lucky rigging a custom shader with bsdf_interior.

 

crabxrayvolumetric.png

 

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