Iray+ Renderers

Iray for 3ds Max includes two renderers, Iray+ and Iray+ Interactive, each tailored to perform specific rendering tasks. This page provides details on how to control and optimize the behavior of each renderer to suit your requirements.

(For details on choosing your renderer, see here.)

Iray+ renderer

The Iray+ renderer tab, which can be accessed by selecting Rendering > Render Setup… from the 3ds Max menu bar, provides controls to optimize rendering behavior and to specify Frame Completion criteria.

Optimization:

• Ray Depth:
  • Max Number of Bounces: controls the extent of raytracing. A lower value will reduce scene accuracy but will speed up rendering.
• Render Output Window:
  • Only Update on Render Completion: maximises render efficiency by showing no updates until the final render.
  • Update Interval (seconds): sets the time interval, in seconds, between updates of the Production Rendering Mode Output window. Increasing this value can result in improved rendering performance; decreasing it can degrade rendering performance but provides more frequent feedback. Your first iteration may take longer than this value to be shown, as the scene's complexity may take longer than your chosen time.
  ✱  Note: Render Output Window control is only available in Production Rendering Mode.
  
  
• Sample Methods:
  • Use Caustics Sampler: transmission effects and caustics will be seen to resolve far quicker, and with more accuracy, but with an increase in render time. In actuality, direct caustics will be accelerated with this sampler; indirect caustics (for example the reflection of a caustic) will still resolve at the same rate.
• Noise Reduction:
  • AI De-noise: applies a powerful post-processing filter to remove noise from a rendered image. This can significantly reduce the render times required to achieve high quality, noise-free images. The filter works on Beauty, Alpha, Diffuse, Glossy, Specular, and Emission Render Elements as well as on Beauty LPE layers.

    AI De-noising is a GPU-only filter, optimised for Pascal-generation (or later) GPUs. Maxwell and Kepler generation GPUs are supported, but overall render performance may be significantly impacted on these devices. The filter also requires significant memory resources to operate and therefore its performance may be limited on GPUs with insufficient available memory.

  • Use Firefly Filter: helps to remove fireflies (bright spots) from the scene. This filter is useful for getting more usable images quickly from complex lighting scenes. Images will be less accurate at low render iterations but will converge to the same result, given sufficient iterations. Initial renders will also appear slightly darker. Be aware that when not using the Caustic Sampler, initial caustic samples appear gradually and so may be removed by this filter.
    ✱  Note: the Firefly Filter requires the Tone Mapper to be enabled in order to function. When the Tone Mapper is disabled, this setting will have no effect.
    
    
• Upscaling:
  • Enable Upscaling: renders the image internally at one half of the specified 3ds Max Output Size, then upscales it to the desired resolution. This results in significantly accelerated rendering performance, at the expense of some reduction in image accuracy. Upscaling requires the AI De-noise filter to be enabled and therefore works only with certain Render Elements and with Beauty LPE layers. (Unsupported Render Elements are inactive when upscaling is enabled.) For best results when upscaling, we recommend also that you enable the Antialias Elements option on the Rendering > Render Setup… > Render Elements tab.
    ✱  Note: upscaling is not compatible with Remote Rendering or Lighting Analysis.
    
    
• Spectral Rendering:
  • Use Spectral Rendering: simulates light transport using a range of wavelengths from 380 to 780 nanometers, rather than using simple RGB values, and computes a color result as the final output. When Spectral Rendering is enabled, we recommend that you use spectral input data to represent colors in your scene. RGB colors or textures can also be used as long as the Input Color Space parameter is set to an appropriate value.
  • Input Color Space: controls how RGB color data is converted to spectral data. You should set it to match the color space in which your RGB colors were defined. If you use spectral data in your scene, this parameter will also have an effect even when Spectral Rendering is disabled. In this situation the spectral data must be converted to RGB colors and this parameter will define the color space of the operation.
  • Output Color Space: sets the color space of the final rendered image.

Frame Completion:

• Passes/frame: defines how many iterations Iray may take before it considers a frame complete.
• Minutes/frame: defines how many minutes Iray may devote to rendering each frame.

  Rendering will stop at the first Frame Completion value reached (for example, if 1000 iterations have been completed before 15 minutes have elapsed).

Iray+ Interactive renderer

The Iray+ Interactive renderer tab, which can be accessed by selecting Rendering > Render Setup… from the 3ds Max menu bar, provides controls to optimize rendering behavior and to specify Frame Completion criteria.

Optimization:

• Ray Depth:
  • Max Number of Bounces: controls the extent of raytracing. A lower value will reduce scene accuracy but will speed up rendering.
• Lighting:
  • Approximate Bounced Light: adds an approximation of indirect light in the scene. This option can not be used with any other Lighting Optimization.
  • Approximate Area Lights: replaces accurate area lights with an approximation based on point lights.
  • Screen Space Shadows: uses ambient occlusion to quickly approximate areas of shadow when using Physical Sky or IBL.
• Noise Reduction:
  • AI De-noise: applies a powerful post-processing filter to remove noise from a rendered image. This can significantly reduce the render times required to achieve high quality, noise-free images. The filter works on Beauty, Alpha, Diffuse, Glossy, Specular, and Emission Render Elements as well as on Beauty LPE layers.

    AI De-noising is a GPU-only filter, optimised for Pascal-generation (or later) GPUs. Maxwell and Kepler generation GPUs are supported, but overall render performance may be significantly impacted on these devices. The filter also requires significant memory resources to operate and therefore its performance may be limited on GPUs with insufficient available memory.

  • Use Firefly Filter: helps to remove fireflies (bright spots) from the scene. This filter is useful for getting more usable images quickly from complex lighting scenes. Images will be less accurate at low render iterations but will converge to the same result, given sufficient iterations. Initial renders will also appear slightly darker. Be aware that when not using the Caustic Sampler, initial caustic samples appear gradually and so may be removed by this filter.
    ✱  Note: the Firefly Filter requires the Tone Mapper to be enabled in order to function. When the Tone Mapper is disabled, this setting will have no effect.
    
    
• Upscaling:
  • Enable Upscaling: renders the image internally at one half of the specified 3ds Max Output Size, then upscales it to the desired resolution. This results in significantly accelerated rendering performance, at the expense of some reduction in image accuracy. Upscaling requires the AI De-noise filter to be enabled and therefore works only with certain Render Elements and with Beauty LPE layers. (Unsupported Render Elements are inactive when upscaling is enabled.) For best results when upscaling, we recommend also that you enable the Antialias Elements option on the Rendering > Render Setup… > Render Elements tab.
    ✱  Note: upscaling is not compatible with Remote Rendering.
    
    

Frame Completion:

• Passes/frame: defines how many iterations Iray may take before it considers a frame complete.
• Minutes/frame: defines how many minutes Iray may devote to rendering each frame.

  Rendering will stop at the first Frame Completion value reached (for example, if 300 iterations have been completed before 5 minutes have elapsed).

See Also:

• Render Setup
• Lighting Analysis

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