Iray Programmer's Manual


Result Canvases

Iray Interactive supports all Canvas names in render targets with the following limitations:

  • The number of texture spaces available through texture_coordinate[ n ] is limited to 1.

  • Iray Interactive cannot render all light path expressions. Light path expressions including global illumination are not supported, i.e., only expressions that capture a subset of "ES*(D|G)?L" are supported.

  • Iray Interactive cannot render the irradiance canvas.


The Iray Interactive material model, which is based on MDL (Material Definition Language), has the following limitations:

  • The number of elemental BDSFs per material are restricted to a maximum of 16.

  • The number of (procedural) texture functions per material are restricted to a maximum of 32.

  • The material volume properties are ignored, i.e., no volumetric effects, except for volume attenuation in glass-like materials.

  • Fractional cutout opacity is not supported. For values less than 0.5, the object is fully transparent; otherwise, the object is fully opaque.

  • The rounded-corners feature is not supported.


Iray Interactive has the following rendering limitations:

  • No volumetric effects except volume attenuation by Beer's law.

  • Emissive geometry is not illuminating the scene, but it is considered when the geometry is hit directly.

  • Non-specular refraction of finite lights is rendered black.

  • No motion-blur.

  • No custom matte objects.

  • The maximum number of light sources is 16.

  • If irt_ambient_shadow_mode != 1 , i.e., when environment shadows are off or when screenspace approximation is used, diffuse roughness is not supported and subtle lighting differences can be visible if the dome is in spherical or hemispherical mode.

  • Environment lighting of diffuse layers does not take into account the dome mode, the dome texture scale parameter and the position and size of the dome. The light is always collected from the infinite environment, applying only the dome rotation parameters.

  • The shadow buffer does not contain glossy reflections of shadow computations on the virtual ground plane.

  • The bloom postprocessing filter and glossy ground plane reflections are disabled during network rendering for performance reasons.


Picking reports only the first hit as a result.

Multi-GPU Configurations

Due to prohibitive inter-GPU synchronization traffic, the following options are not available in multi-GPU configurations:


The "user" instancing mode is not supported in Iray Interactive