This page provides information on the Image sampler rollout under the V-Ray tab.
Overview
Example: What is anti-aliasing?
One of the purposes of sampling is to improve anti-aliasing. The following example shows the difference between an image with Image Sampler Subdivs locked to 1 and an image with the default Max Subdivs value of 24.
In the image with anti-aliasing (Default Max Subdivs of 24), the edges appear smoother than in the image without anti-aliasing (Locked to 1).
V-Ray performs anti-aliasing by sampling colors in areas where one color meets another, as with the edges touching the background. The choice of image sampler and the parameter settings determines the effectiveness of anti-aliasing for any particular scene.
Anti-aliasing within a material can also be affected by filters, such as those included with 3ds Max. V-Ray image samplers support most 3ds Max filters.
Image Sampler Subdivs locked to 1
Image Sampler Subdivs locked to 24
Parameters
Example: Min Shading Rate
The Min shading rate of the first image is set to 1, while that of the second image is set to 16.
Min shading rate is set to 1
Min shading rate is set to 16
Both of the images above rendered with the Progressive image sampler for the same amount of time. With Min Shading rate set to 16, at least 16 GI rays are shot for each AA ray, which produces smoother GI, but overall leads to less samples left for the DOF effect.
Choosing the Best Image Sampler for the Situation
No image sampler is best for all scenes or workflows. Choosing the best image sampler is usually a matter of experimentation, but there are a few guidelines you can follow. For additional information, see the Progressive Image Sampler and Bucket Image Sampler pages.
- Setting Image Sampler Type to Bucket is the same as the Adaptive Type in previous versions of V-Ray.
- With the Bucket type, disabling Max. Subdivs also disables the Noise threshold and matches the Fixed sample behavior in earlier versions of V-Ray.
- Progressive is useful when it is necessary to see overall results quickly (like when placing light, building shaders, or general Look Development work) because it generates the whole image at once and progressively cleans up the noise in it. Additionally, the render can be stopped at any time before resolving completely.
- Progressive is also helpful when a set amount of time to spend per render is needed. This can also be useful when rendering test animations, where the entire sequence must be rendered within a certain time frame.
- Combining the VRayDenoiser with Progressive renders can help with cleaning up render noise. If the Denoiser's Update button is used when manually canceling a render, the noise levels will be adequate enough to use the denoiser to avoid splotches and/or other unwanted effects. Also note that in 3ds max 2017, there is a Stop button in addition to the Cancel button in the progress window. After clicking Stop, V-Ray begins denoising the render.
- Using Bucket when running Distributed Renders can be helpful for cutting down on network traffic and reducing the loss of information if work is not completed by one or more DR machines.
Image Samplers and RAM Usage
Image samplers require a substantial amount of RAM to store render information. This is especially true for the Progressive sampler, which stores the entire image in memory before beginning the rendering process. The Bucket sampler, on the other hand, stores only the summed result of all sub-samples for a pixel and so usually requires less RAM. Using large bucket sizes might require more memory.