Octane Path Tracing Kernel
Path Tracing is best used for realistic results (together with PMC). The render times are higher than Direct Lighting (but the results can be photorealistic. It can have some difficulties with small light sources and proper caustics (for which pmc is better suited).
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. There is no rule as to how many samples per pixel are required for a good render.
Maximum Diffuse and Glossy Depth: The maximum number of times a ray can bounce/reflect/refract in a surface. Higher amounts mean also higher render time but more realistic results. For outdoor renders, a good setting is around 4 maxdepth. For lighting interior with natural light (the sun and the sky) you will need higher settings such as 8 or higher to allow enough light to bounce around in the scene. While high values are possible, in reality rays will not usually go beyond 16 ray depth.
Ray Epsilon: The 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.
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. There is no rule as to how many samples per pixel are required for a good render.
Filter Size: This sets the pixel size for filter for the render. This can improve aliasing artifacts in the render. If the filter is set too high, the image can become blurry.
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.
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.
Caustic Blur: This is used to approximate caustics on rough surfaces and increase or decrease the sharpness of caustic noise. A zero value provides the sharpest caustics, and increasing this value increases the blurring effect to make caustics appear softer.
GI Clamp: It clamps the contribution for each path to the specified value. By reducing the “GI clamp” value, you can reduce the amount of fireflies caused by sparse but very strongly contributing paths. Reducing this value reduces noise by removing energy. On the other hand, “caustic blur” reduces noise by blurring caustics, but conserves energy.
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.