Sampling

• Sampler

  • Uniform: Every pixel is sampled the same number of times.
  • Adaptive: Sampling is based on whether or not a tile has reached a certain noise threshold.
  • Texture-Based: Sampling is weighted by a black and white image map that is overlaid on the render window. Black areas sample less, white areas sample more.

• Passes

  The number of times the sampler will loop over all the pixels in the image. [1] [2]

• Uniform Sampler

  • Samples: The number of samples taken per pixel per pass.

• Adaptive Sampler

  • Batch Size: The number of pixel samples taken in between noise evaluations.
  • Max Samples: The total number of samples that can be taken per pixel per pass.
  • Noise Threshold: The level of noise that is acceptable in the final image. A pixel will render until it hits this limit or the max samples.
  • Uniform Samples: The number of uniform samples that are taken before adaptive sampling kicks in. This is necessary to ake sure fine details are captured in the image before noise evaluations start.

• Texture-Based Sampler

  • Texture Path: This is the location of the texture that will be used to guide sample counts.
  • Min Samples: The number of samples taken for black areas of the guiding map.
  • Max Samples: The number of samples taken in white areas of the guide image.

• Interactive Render

  • FPS: The maximum framerate of the interactive render session.
  • Max Samples: The number of samples taken before rendering halts in interactive mode.
  • Max Time in Seconds: The length of time the interactive render will run in seconds before pausing.

• Tile Pattern

  • Pattern: The order in which tiles are selected during rendering. Pick anything other that random.
  • Tile Size: This is the size of the tiles that the image is broken into for rendering.

• Pixel Filter:

  • Filter: This is the type of filter used for image reconstruction.
  • Filter Size: The size of the filter kernel.

Footnotes

[1]	Setting the passes higher than 1 and lowering the number of samples enables a featured called ‘progressive rendering’. The image will appear in its entirety after one pass and noise will be subsequently reduced with each additional pass.

[2]

Progressive rendering is slower than single pass rendering, however it does have its advantages. If you are not certain how many samples will be needed to create a clean image, you can set the samples to a low number and the passes number to a higher one. When the image has reached an acceptable level of quality the render can be aborted.