Denoise Otoy OctaneRender with Altus

Warning

This article is under construction and will be updated. More information coming soon.

Overview

Altus Denoiser uses information from two rendered images to generate a high quality denoised image. This guide will explain how to setup and render the inputs to Altus. There are two concepts that Altus uses to generate denoised outputs:

AOVs (Arbitrary Output Variables) provide a way to render any arbitrary shaded component into different images. Typically renderers will only produce a final color for each pixel of the image (known as the beauty pass, or RGB pass), but you can break out renders into their component parts such as indirect lighting, diffuse color, reflections, shadows, mattes, etc. and save them as files individually or layers as part of a multichannel/multilayer EXR. See Recommended AOVs for more information.

Two images (called buffers) must be generated for each image. It’s important that each buffer is rendered with a different sample seed so that they will have unique noise patterns. The variance between the two buffers is what Altus uses to remove noise. Without variance, there is not enough information to remove noise. See Buffers for more information.

For information on how to run Altus once the correct inputs have been created see Usage.

Exporting AOVs

Recommended List of AOVs to use with Altus:

AOV type Altus Input Name Octane Render Pass Name
World Position pos Position
Bump Normals nrm Shading Normals
Visiblity vis Shadow / AO
Albedo alb Diffuse Filter
Reflection extra Direct/Indirect Reflection
Caustics cau (Optional) N/A

How to Output AOVs that are compatible with Altus (from OctaneRender)

Warning

Please upgrade to OctaneRender 3.06 or later, as earlier versions to not support generation of the visibility AOV. See Recommended AOVs.

Add AOVs to save from OctaneRender by opening the Render Settings Panel. Then switch to the Render Passes tab. This is where all the available Render Passes will be listed. Add as many passes as you prefer. For more information on render passes see https://help.otoy.com/hc/en-us/articles/115001714766-Render-Passes

../../_images/Octane_Render_Passes.png

Saving AOVs

These added AOVs can be written to an EXR images along with the beauty render by using the buttons below the viewer:

../../_images/Octane_Save_Output_highlight.png

Exporting Two Buffers

Altus requires two renders (called buffers) of the same scene to denoise properly. Octane offers a few methods to render and save two buffers for Altus.

Render Twice

You can render twice and change the sample seed between renders. Octane doesn’t support changing the render seed directly, however, it has a setting Static Noise which locks the seed across frames when rendering animations. Static Noise will select a different seed when toggled on/off. Using that setting you can force octane into using a different seed by enabling Static Noise to render b0, and disable it to render b1. This way each buffer will have a unique sample seed and noise pattern.

Before rendering b0, ensure that ‘Static Noise’ is turned on in the Kernel settings panel under the Render Settings:

../../_images/Static_Noise_enabled_highlight.png

Once the b0 render is completed, turn ‘Static Noise’ back off and start the second render for b1.

../../_images/Static_Noise_highlight.png

Note

If you want better integration with OTOY Octane request a sample seed option.

Render Once with Side-by-Side

You can render once using a side-by-side (stereo) camera rig and Altus will divide the image into two buffers. The camera’s (eye) separation should be set to 0.0 so the left and right camera’s have the same location and their renders will be identical except for the noise pattern.

Warning

This is not creating stereoscopic imagery; it is a mechanism to create the two buffers Altus needs without having to render twice.

../../_images/Octane_Stereo_highlight.png

For more information on side-by-side stereo rendering in Octane: https://help.otoy.com/hc/en-us/articles/115001664266-Camera-Settings