This pages presents the Iray renderer available in the 3D view panel of Substance 3D Designer, which offers interactive path tracing for photorealistic rendering with CPU and/or GPU acceleration (Nvidia GPUs only).

In this page

Overview

3D view options

Hardware acceleration

3D view options

The following options are available for adjusting the rendered scene:

Scene

Select the Edit option in the Scene menu to find scene properties specific to Iray in the Properties panel.

• Is enabled: When set to False, the object is hidden and no longer contributes to the scene

Display component

• Is visible: When set to False, the object is hidden yet still contributes to the scene – i.e. reflecting light, absorbing light and projecting shadows

Mesh display component

• Subdivision
  • Method: The method used to procedurally subdivide the mesh into finer geometry
    • None: No subdivision is applied
    • Parametric: Subdivides the mesh into 4^x triangles where x is the value specified by this parameter
    • Length: Subdivides the mesh until all edges have a length (in object space) below the value specified by the Minimum length parameter
  • Minimum length: Subdivides the mesh until all edges have a length below this specified value in object space (only applies to the Length method)
  • Number: The number of subdivision iterations which should be applied to the mesh (only applies to the Parametric method)

Materials

Since Iray relies on the MDL shading model developed by NVIDIA, available materials for scene materials are replaced with the MDL library loaded by Designer. This library is built using the following sources:

• The MDL files included in Designer's installation
• The MDL files found in the directories listed by the user in the loaded Project files
• The NVIDIA vMaterials library if it is installed

Camera

The main difference between OpenGL and Iray regarding camera settings is how depth of field is managed. Indeed, Iray being a physically-accurate renderer, depth of field occurs "naturally" depending on the camera's aperture.

The following couple of parameters are available in the camera properties when the Iray renderer is selected:

• Focus distance: the distance from the camera of the focal point – i.e. where the image is at its sharpest
• Aperture diameter: the value driving the camera's aperture. The lower the value, the sharper the image elements are before and after the focal point – in simpler terms, this value controls the strength of the depth of field effect

Environment

Open the Environment menu and select the Edit option to display the environment properties in the Properties panel.

The following properties are available:

Dome

• Dome type: sets the objects enclosing the scene, which the environment texture is projected on
  • Infinite sphere: infinite spherical environment
  • Ground: infinite spherical environment, but with a textured ground plane
  • Sphere: finite size sphere-shaped dome of custom radius
  • Sphere with ground: finite size sphere-shaped dome with custom radius where the lower part of the environment is projected onto the plane dividing upper and lower parts of the sphere
  • Box with ground: finite size box-shaped dome of custom width, height and length where the lower part of the environment is projected onto the plane dividing upper and lower parts of the box
• Rotation angle: controls the angle of rotation of the dome around the Y axis
• Radius: the radius of the sphere (only applies to the Sphere and Sphere with ground dome types)
• Width: the width of the box (only applies to the Box with ground dome type)
• Height: the height of the box (only applies to the Box with ground dome type)
• Length: the length of the box (only applies to the Box with ground dome type)
• Visualize: enables a false-color overlay of the finite size environment geometry. This can be used to align the geometry with the projection of the captured environment map (only applies to the Sphere, Sphere with ground and Box with ground dome types)

Dome ground
The following parameters apply to the Ground, Sphere with ground and Box with ground dome types:

• Ground: enables the ground plane
• Position: the position of the origin of the finite dome (also applies to the Sphere dome type)
• Reflectivity: the opacity and tint of the ground reflection, where black means the reflection is not visible
• Glossiness: the glossiness of the ground reflection
• Shadow intensity: the opacity of the shadow cast on the ground
• Texture scale: controls the size of the environment texture projection on the ground (also applies to the Sphere dome type)

The impact of some of these settings is demonstrated below:

Display

These options display a text overlay on top of the rendered image with useful information regarding the render.

• Elapsed time: The duration of the render in seconds. This timer and the rendering process will both stop when one of the ending conditions are met
• Iterations: The number of sampling iterations performed. This counter and the rendering process will both stop when one of the ending conditions are met
• Rendering method: The rendering pathway used. For most purposes on a local machine, Photoreal is used
• Resolution: The effective rendering resolution. If the Use window resolution option in the camera properties is set to False, the ratio of the image is automatically adjusted to match the resolution ratio
• Scene stats: A list of statistics related to the rendered scene, which includes triangles count, and materials count among other data

Renderer

Open the Renderer menu and select the Edit option to display the renderer properties in the Properties panel.

Progressive rendering

• Min samples: The minimum number of samples per pixel to compute before considering criteria to stop progressive rendering
• Max samples: If this number of samples per pixel has been rendered, then stop progressive rendering automatically
• Max time (seconds): Time in seconds after which progressive rendering should terminate automatically

• Caustic sampler enabled: Augment the default sampler with a dedicated caustic sampler. Caustics are a result of light passing through a non-opaque object, thus is required only if an MDL material supporting translucency is applied on any object in the scene

• Firefly filter enabled: enable the firefly filter, which uses a predefined algorithm to remove fireflies in the computed image as rendering progresses. Fireflies are visual artifacts where isolated pixels in an image which are noticeably brighter than their neighbours, and are a result of unsufficient ray samples to accurately determine the distribution of light

• Post denoiser
  The Iray renderer uses the NVIDIA Optix AI-Accelerated denoiser algorithm for iterative high-quality denoising of the image as it is being rendered.

  • Enabled: enables a predefined denoising algorithm to be triggered at a set rendering iteration, and be active until the end of the render
  • Start iteration: If the denoiser is enabled, this option sets the iteration at which the denoising process starts. This can prevent the denoiser's performance overhead from impacting interactivity, for example, when moving the camera. Additionally, the first few iterations are often not suitable as input for the denoiser due to insufficient convergence, leading to unsatisfactory results.

The impact of some of these settings is demonstrated in the image comparisons below:

Material: Thick glass MDL available in the MDL Core definitions by NVIDIA

Hardware acceleration

The Iray renderer offers hardware acceleration on NVIDIA GPUs exclusively, which offers the following benefits:

• Significant increase of rendering speed
• Optix AI-Accelerated denoising (see "Post-denoiser" in the Renderer section of this page)

You may select the hardware which should be used by Iray for rendering in the 3D View section of the Preferences window, as shown in the image on the right.

When a supported GPU is detected, it is listed in this section, is automatically selected by default and the CPU is unselected. Any manual change overrides this automatic behaviour so your custom changes are saved for future sessions.