Iray for 3ds Max has two renderers, Iray+ and Iray+ Interactive. Iray+ renderer delivers the best results, and is a good choice as your production renderer. Iray+ Interactive allows easier navigation within your scene, and images resolve faster; this is a good choice for an ActiveShade renderer. Iray+ also contains a Lighting Analysis mode which allows you to simulate and monitor the minimum and maximum lighting levels in your scene.
Interactive Rendering using Iray+ and Iray+ Interactive
Passes/Frame: Defines how many iterations Iray will take before considering a frame complete
Minutes/Frame: Defines how many minutes Iray will take rendering each frame.
✱ Note: Rendering will stop at the first Frame Completion value reached (e.g. 1000 passes reached before 60 mins).
Optimization
Ray Depth: Increases or decreases the extent of the raytracing; a lower number will reduce scene accuracy but will speed up rendering.
Render Output Window (Production Renderer only):
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 Render Output window. Increasing this value can result in improved rendering performance. Decreasing 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.
Sample Methods:
Use Caustic 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 that 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: A powerful post-processing filter that can be used to remove noise from a rendered image. This can significantly reduce the render times required to achieve high-quality and noise-free images. The filter works on Beauty, Diffuse, Glossy and Specular render layers 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 cards are supported, but overall render performance may be significantly impacted on these cards. The filter also requires significant memory resources to operate and therefore the performance may be limited on any cards with insufficient available memory.
Use Firefly Filter: Helps remove fireflies (bright spots) from the scene; useful for getting more usable images
quickly from complex lighting scenes. Your image will be less accurate at low render iterations but will converge to the same result,
given enough 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.
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 Colour Space: This parameter sets the color space of the final rendered image.
Passes/Frame: Defines how many iterations the renderer will take before considering a frame complete
Minutes/Frame: Defines how many minutes Iray will take rendering each frame.
✱ Note: Rendering will stop at the first Frame Completion value reached (e.g. 1000 passes reached before 60 mins)
Optimization
Ray Depth: Increases or decreases the extent of the raytracing; a lower number will reduce scene accuracy but will speed up rendering.
Lighting:
Approximate Bounced Light: Adds an approximation of indirect light in the scene. Can't 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 lighting.
Noise Reduction:
AI De-Noise: A powerful post-processing filter that can be used to remove noise from a rendered image. This can significantly reduce the render times required to achieve high-quality and noise-free images. The filter works on Beauty, Diffuse, Glossy and Specular render layers 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 cards are supported, but overall render performance may be significantly impacted on these cards. The filter also requires significant memory resources to operate and therefore the performance may be limited on any cards with insufficient available memory.
Use Firefly Filter: Helps remove fireflies (bright spots) from the scene; useful for getting more usable images
quickly from complex lighting scenes. Your image will be less accurate at low render iterations but will converge to the same result,
given enough 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.
