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Solaris and Karma » Ocean and Karma
- dlee
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Houdini Lounge » Looking for some Karma tips
- dlee
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Hi. Yes, the reason why mantra render is so fast is because there's no light in the scene, so everything is lit via unshadowed headlight. Karma is automatically creating geometry lights based on material emission on “arches” and “light” geometry, so the lighting is far, far more complex. Additionally karma render has diffuse indirect bounce enabled by default and mantra has it disabled by default. To avoid artifacts around the arches due to motion blur, I'd recommend increasing the minimum sample count on variance pixel oracle (2 isn't enough in this case and causing some buckets to terminate prematurely).
Edited by dlee - Oct. 27, 2020 17:21:10
Solaris and Karma » Light Expression Help with refractions
- dlee
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Hi. The distinction between direct and indirect is the number of scattering events. If there's only one between the camera and the light, then it's direct. If there's more, then it's indirect.
So, direct refraction could be:
C<TG>L
Indirect refraction:
C<TG>.+L
You could substitute
So, direct refraction could be:
C<TG>L
Indirect refraction:
C<TG>.+L
You could substitute
[LO]
for L
if you want to count emissive objects as lights.
Technical Discussion » Toon Shader Custom AOVs
- dlee
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Hi. I don't see why the first set up wouldn't work. Can you post an example file?
Edited by dlee - Sept. 19, 2020 10:58:00
Technical Discussion » Karma sss bucket issue
- dlee
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Do you see the same issue using the latest daily build? If so, can you file a bug with an example scene, please?
Solaris and Karma » Normal to have different results Viewport vs Offline? (SSS)
- dlee
- 419 posts
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Agreed. This (among others) is the reason why next major release of karma will have a setting to decide the sampling behaviour so that both IPR and offline rendering produce identical result.
Solaris and Karma » Normal to have different results Viewport vs Offline? (SSS)
- dlee
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The differences are likely due to firefly clamping (“Color Limit” parameter). In 18.0, karma offline rendering uses per-component sampling which takes multiple SSS samples per camera ray and averaged, so spectral scattering with high amount of contrast is less likely to get clamped and cause tonal shift. You can increase “Color Limit” to fix the problem in IPR. There's currently a bug in 18.0 where changing this parameter seemingly doesn't do anything unless you restart the render - we'll be addressing it very shortly.
Solaris and Karma » Black pixel artifacts in Karma (Random Walk SSS)
- dlee
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Upcoming daily build (18.0.469) will have reduced noise in offline rendering (for random walk SSS) and fix the ugly tiling artifacts when adjusting SSS Samples parameter.
Edited by dlee - May 16, 2020 18:32:22
Solaris and Karma » Black pixel artifacts in Karma (Random Walk SSS)
- dlee
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Yikes. Overriding SSS Sample count seem severely broken - investigating. The other noise issues that remain despite high camera sample count is due to known issue with RNG in 18.0.
Solaris and Karma » Moana Island into USD with Solaris
- dlee
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FYI, 18.0.466 adds ptex support to karma. I know you've already gone through the trouble of converting the assets, but figured to let you know in case you wanted to try it out.
Solaris and Karma » Oceanshader with Karma
- dlee
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jsmack
Is it possible to enable the equivalent of ‘vm_volumesurface’ in karma so the volume and surface shaders can be assigned to the same mesh (using a dPdz switch)?
Not currently, no.
Solaris and Karma » Oceanshader with Karma
- dlee
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Ocean shader mostly works - currently displace exports are unsupported in karma, so things like foams will be missing.
To render ocean volume, you need to use Rende Geometry Settings LOP on the interior geometry and enable “Uniform Volume” and set the “Uniform Volume Density” to match the cloud density in the ocean volume shader (not the most ideal workflow… we're hoping to address it in the future).
Also, SOP/Scene import will bring in display nodes, not render nodes. If you're using ocean shelf tools to create ocean objects, you may have noticed that display and render flags are not on the same node. You need to set the display flag on the render node to have it imported into LOPs.
To render ocean volume, you need to use Rende Geometry Settings LOP on the interior geometry and enable “Uniform Volume” and set the “Uniform Volume Density” to match the cloud density in the ocean volume shader (not the most ideal workflow… we're hoping to address it in the future).
Also, SOP/Scene import will bring in display nodes, not render nodes. If you're using ocean shelf tools to create ocean objects, you may have noticed that display and render flags are not on the same node. You need to set the display flag on the render node to have it imported into LOPs.
Solaris and Karma » Cannot get LPEs to work with LPE Tag
- dlee
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As long as the shader has the VEX export, you can write it to an AOV. Principled/classic shader exports basecolor as “export_basecolor”, so in your karma or karma render properties LOP, create a new “Extra Render Var”, set it to “color3f” format, and set as “Source Name” as “export_basecolor”. (without quotes)
Solaris and Karma » Cannot get LPEs to work with LPE Tag
- dlee
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Hi. The existing LPE tag properties are for mantra only. There's currently no way to specify tags for Karma at the moment.
Solaris and Karma » Rotating dome light
- dlee
- 419 posts
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Solaris and Karma » Black pixel artifacts in Karma (Random Walk SSS)
- dlee
- 419 posts
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I'm rendering the scene you provided in a loop, but so far I'm unable to reproduce the crash. may I ask what command line arguments you're passing into husk?
@Werner: did you mean build 393?
@Werner: did you mean build 393?
Solaris and Karma » Black pixel artifacts in Karma (Random Walk SSS)
- dlee
- 419 posts
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Scene Import would've preserved the transforms, so I assume your renders were affected as well.
Solaris and Karma » Black pixel artifacts in Karma (Random Walk SSS)
- dlee
- 419 posts
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Solaris and Karma » Black pixel artifacts in Karma (Random Walk SSS)
- dlee
- 419 posts
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Do you have scale applied to the object? Currently there seems to be a bug with random walk where it can behave erratically with scaling which might account for larger differences (this will be addressed shortly).
Solaris and Karma » Solaris Portal Lights?
- dlee
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