This page provides information on the Bucket Image Sampler rollout in the V-Ray tab of the Render Settings.
The diagram on the right shows the way V-Ray places samples when using the Bucket sampler type in the Image Sampler rollout. The black squares represent the pixels of the image while the dots represent the individual samples. In the first pass, V-Ray always places the minimum number of samples determined by the Min subdivs parameter. Then, the color of samples is compared and more are added where needed in the following passes.
||Render Setup window|| > V-Ray tab > Bucket image sampler rollout
(When V-Ray is the Production renderer and the Image sampler type is set to Bucket)
This rollout appears when the Type in the Image sampler (Antialiasing) rollout is set to Bucket. This sampler adaptively makes a variable number of samples per pixel based on the difference in intensity between the pixel and its neighbors.
Min subdivs – Determines the initial (minimum) number of samples taken for each pixel. You will rarely need to set this to more than 1, except if you have very thin lines that are not captured correctly, or fast moving objects if you use motion blur. The actual number of pixels is the square of this number (e.g. 4 subdivs produce 16 samples per pixel).
Max subdivs – Determines the maximum number of samples for a pixel. The actual maximum number of sampler is the square of this number (e.g. 4 subdivs produces a maximum of 16 samples). Note that V-Ray may take less than the maximum number of samples, if the difference in intensity of the neighboring pixels is small enough.
Noise threshold – The threshold used to determine if a pixel needs more samples.
Bucket width – Determines the maximum region width in pixels.
Bucket height – Determines the maximum region height in pixels.
L button – Locks the height of the bucket to be the same as the width size.