Podium Walker Iray - Samples/Quality
1. Samples: Image quality in Podium Walker is directly related to the number of samples calculated by Iray for each frame of an animation (or still image).
What is progressive rendering?
In progressive rendering, the entire image is calculated in increments called samples. Each new sample increases the accuracy of the image—first shapes and edges are resolved, light distribution and material characteristics become more realistic, and Iray gradually cleans up noise and artifacts until a clean render is produced.
Unlike SU Podium, an Iray render is never technically "finished." Podium Walker will continue running calculations until the user tells it to stop, usually at a point of diminishing returns where additional samples do not add visibly to the quality of the image. Take a look at the images below for a demonstration of progressive rendering.
Photo-real mode - 10, 100, 500, 5000 samples:
Notice in the above example using Iray photo-real mode, 5000 samples is not sufficient to fully eliminate the noise. Required samples will vary from model to model; for this scene, at least 10,000 samples would be recommended.
Id mode generally requires fewer samples:
In contrast to the above example, the following image was rendered in Podium Walker's ID mode with 1000 samples, and as you can see the noise is more or less eliminated.
ID mode simulates indirect light, but uses a "biased sampling algorithm" instead of true brute-force pathtracing to speed up the render process. Technically, the render is less physically accurate, but image quality is still quite good. For rendering animation, ID mode is vastly more efficient than PR mode without a drastic quality hit.
Photo-real mode has advantages for still visualization:
Given time to calculate enough samples, Podium Walker's PR mode will yield the best image Iray is capable of, with superior reflection quality and light distribution. Pr mode is also the only render mode that supports SU Podium light emitting (LEM) materials, which can be extremely useful when lighting a scene.
In the following example with 10,000 samples, noise has been reduced almost to the point of invisibility:
2. Render settings Gear icon
Podium Walker gives you three ways to set the number of samples that will be calculated for each image or frame of an animation. Quality settings are accessed via the gear icon.
- Time: Sets a maximum time limit per frame. Podium Walker calculates additional samples until the time limit is reached, and either saves a still image or moves onto the next frame.
- Samples: Specifies a precise number of samples per frame. Use this if you've already done test renders and know how many samples are required for your desired image quality.
- Automatic: An automatic solution that attempts to find an efficient balance between speed and quality. Moving the slider toward "fine" yields higher quality imagery (more samples) but slower render times.