Iray Programmer's Manual

Limitations

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 general light path expressions, i.e., result canvases of the form lpexpr= lp-expression. However, the pre-defined result canvases diffuse , specular , glossy , and emission are available.

  • Iray Interactive cannot render the irradiance canvas.

Materials

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.

Rendering

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 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.

  • Glossiness of the virtual ground plane is not supported. If the value of environment_dome_ground_glossiness is set to a value above 20000 the ground plane becomes specular reflective. For lower values, it does not reflect at all.

  • Light profiles are only supported on point lights.

Picking

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: