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Rendering with Arnold in CINEMA 4D using the C4DtoA plug-in.
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Adaptive Sampler & Custom Filters

Message 1 of 12
293 Views, 11 Replies

Adaptive Sampler & Custom Filters

I'm trying to setup the AOV to show the sample density as mentioned in the docs, however the AA_inv_density AOV appears black. I changed the filter to heat map but the docs mention a AiAOVSampleIteratorGetInvDensity() function call, not sure what to do with this?

Message 2 of 12

Are you using adaptive sampling? AA_inv_density works with adaptive sampling only.

We'll update the docs. This sentence is in the wrong section:

The AA_inv_density AOV can help to visualize the sample density with Adaptive Sampling. Use it with a heatmap filter.

// Stephen Blair
// Arnold Renderer Support
Message 3 of 12

Yes, I was trying adaptive sampling but the the AOV appears black. I had the Heatmap filter on under the Main>Sampling section.

Message 4 of 12

What's the max samples for adaptive? Try putting that as the maximum for the heatmap filter.


I would expect blue, not black. 

// Stephen Blair
// Arnold Renderer Support
Message 5 of 12

I had 6 max originally - tried the default 20 and it was the same.

Message 6 of 12

And you get black in the Arnold IPR Window?
With just default settings, you should be getting some blue. Try with a simpler scene.

// Stephen Blair
// Arnold Renderer Support
Message 7 of 12

I do.


Tried a blank scene with just a cube, plane and a skydome. When I select the AA_inv_density AOV from the IPR it's black. 

Message 8 of 12

And you set the filter to heatmap?


// Stephen Blair
// Arnold Renderer Support
Message 9 of 12

Yes, just like in the screenshot in post #5.

Message 10 of 12

I can see a heat map effect in the beauty, but I'm under the impression I should see something in the AA_inv_display AOV?

Message 11 of 12

You should change the filter for AA_inv_density only, not for the beauty.

beauty should be using the driver filter (gaussian), and AA_inv_density should be using heatmap

The attached zip archive has a Cinema 4D 2023 scene that works.

// Stephen Blair
// Arnold Renderer Support
Message 12 of 12



So the denser areas on the heat map are those that will get more adaptive sampling?


I'm trying to get a decent render time on this interior, it took just over 2 hours on 32 cores. Not sure if that is representative or not. Sampling settings attached. 

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