Octane Direct Lighting Kernel

Maximum Samples: This sets the maximum number of samples per pixel before the rendering process stops. The higher the number of samples per pixel, the cleaner the render. For quick animations and scenes with predomi­nantly direct lighting, a low amount of samples (500-1000) may suf­fice. In scenes with lots of indi­rect lighting and mesh lights, a few thousand samples may be required to obtain a clean render.

GI Type: There are five different Global Illumination modes in the Direct Lighting Kernel:

• None: Only direct lighting from the sun or area lights is included. Shadowed areas receive no contribution and will be black.

• Ambient Occlusion: Standard ambient occlusion. This mode can often provide realistic images but offers no color bleeding.

• Diffuse: Amount of diffusion, or the reflection of light photons at different angles from an uneven or granular surface. Used for dull, non-reflecting materials or mesh emitters.: Indirect diffuse, with a configuration to set the number of in­direct diffuse bounces to include. This gives a GI quality that is in between Ambient Occlusion and pathtracing, without caustics and a decent realistic quality (better than AO), but much faster than pathtracing/PMC. It is very good for quick finals and animations. It is similar in some ways to 'bruteforce' indirect GI in other engines.

Specular depth controls the number of times a ray can be refracted before dying. Higher numbers mean higher render times but more color bleeding and more details in transparent materials. Low numbers can introduce artifacts, or turn some refractions into pure black.

Diffuse Depth: Gives the maximum number of diffuse reflections if GI Mode is set to Diffuse (4)

Glossy depth controls the number of times a ray can be reflected before dying. Higher numbers mean higher render time. Low numbers under “4” can introduce artifacts, or turn some reflections into pure black. You should setup this setting based on the complexity of the scene you are working on, and especially based on how many reflective parallel surfaces you have.

AO Distance: The distance of the ambient occlusion in units. Always check if the amount is right related to your model scale. For example you don't need an amount of “3” units if your object is a small toy. But if your model is a house or something large, you can increase the value. The more you increase the value the darker your render will be.

Ray Epsilon is the distance to offset new rays so they don't intersect with the originating geometry. If the scale of your scene is too large, precision artifacts in the form of concentric circles may appear. In that case, increasing the ray epsilon can make these artifacts disappear.

AO Distance: The distance of the ambient occlusion in units. Always check if the amount is right related to your model scale. For example you don't need an amount of “3” units if your object is a small toy. But if your model is a house or something large, you can increase the value. The more you increase the value the darker your render will be.

Alpha Shadows: This setting allows any object with transparency (specular materials, materials with opacity settings and alpha channels) to cast a proper shadow instead of behaving as a solid object.

Nested Dilectrics: If disabled, the surface IORs are not tracked and surface priorities are ignored.

Irradience Mode: This renders the first surface as a white Diffuse material. Irradiance Mode works similar to Clay Mode, but it applies to just the first bounce. It disables the Bump channel and makes samples that are blocked by backfaces transparent.

Max Subdivision level: Sets the maximum subdivision that is generated for Octane Rendering.

Alpha Channel: This option removes the background and renders it as transparent (zero alpha). This can be useful if the user wants to composite the render over another image and does not want the background to be present.

Keep Environment: Keeps lighting from the simple environment color.

AI Light: Activate AI Light

AI Light Update: Checkbox available when AI light is active.

Light IDS Mask Action: Disble/Enable

Path Term Power: this is the path termination strategy. The default setting should be good in most cases. If some dark patches stay too noisy too long, you can lower the value, which will slow down rendering, but cause Octane to spend more time on those areas.

Coherent Ratio: This feature increases the render speed, but causes some “flickering” during the first samples/pixel and should be mainly used for the final rendering and if only if you plan to render 500 samples/pixel or more. This feature is always disabled in the IPR window. The percent parameter allows you to blend between non-coherent rendering (0%) and “super-coherent” rendering (100%). Please be aware that for values above 0.4 you will usually need a few thousand samples per pixel to get rid of visible artifacts and values above 0.5 hardly ever make any sense.

Static Noise: When enabled, the noise is static, i.e. doesn't change between frames.

Parallel Samples: Controls how many samples Octane calculates in parallel. Smaller values require less memory to store the sample's state, but causes slower renders. High values require more memory, but reduce the render time. The change in performance depends on the scene and the GPU architecture.

Max Tile Samples: Controls the number of samples per pixel that Octane renders before storing the result in the render buffer. Higher values mean that results arrive less often in the film buffer.

Minimise Net Traffic: Distributes the same tile to the net render slaves until Octane reaches the maximum number of samples per pixel for that tile, and then it distributes the next tile to slaves. This option doesn't affect work done by local GPUs. A slave can merge all of its results into the same cached tile until the master switches to a different tile.

Adaptive Sampling: Enables Adaptive Sampling.

Noise Threshold: Specifies the smallest relative noise level. When the noise estimate of a pixel is less than this value, sampling switches off for this pixel. Good values are in the range of 0.01 - 0.03. The default is 0.02, which is pretty clean.

Min Samples: Specifies the minimum number of samples to calculate before adaptive sampling kicks in. A pixel's noise estimate has a large initial error. The higher you set the noise threshold, the higher you should also set this parameter to avoid artifacts

Expected Exposure: This value should be close to the same value as the image's exposure, or 0 (the default value) to ignore these settings. Adaptive sampling uses this parameter to determine what pixels are bright and dark, which depends on the Octane Imager's exposure setting. If the value is not 0, adaptive sampling adjusts the noise estimate of the image's very dark areas. It also increases the Min. Adaptive Samples limit for very dark areas, because very dark areas tend to find irregular paths to light sources, resulting in over-optimistic noise estimates.

White Light Spectrum: Either choose D65 (Adapts to a reasonable daylight "white" color) or Legacy/Flat (Preserves the appearance of old projects (spectral emitters will appear bluer))

Deep Image: Deep image rendering stores the Z-depth location of an object with samples of a rendered image. It works best in scenarios where traditional compositing techniques fail, such as compositions where masking out overlapping objects is too difficult, or scenes that render images images using depth-of-field or motion blur, or compositing footage in rendered volumes. Instead of having single RGBA values for a pixel, a deep image stores multiple RGBA channel values per pixel together with a front and back Z-depth (Z and ZBack channels, respectively). This combination (R, G, B, A, Z, ZBack) is called a deep sample.

Max Depth Samples: When Deep Image Rendering is enabled, this sets the maximum number of depth samples per pixel.

Depth Tolerance: When Deep Image Rendering is enabled, Octane merges the depth samples whose relative depth difference falls below this value.

Toon Shadow Amount: This is the ambient modifier of Toon Shadowing.