• Unbiased-like engine.
  • Designed for fast Interactive rendering.
  • Minimal Settings
  • Used in both Production & Interactive Mode.
  • CPU & GPU


  • Supersampling: Improves antialiasing of the rendered image at the expense of increased memory.
    None: No Supersampling, Normal: 2×2, High: 3×3 and Auto: none for Interactive, 2×2 for Production
  • Tracing Depth: Controls the tracing depth of Diffuse, Reflective & Refractive surfaces.
  • Extended Tracing: Extra tracing depth for Transparent & Subsurface Scattering surfaces.
    Values defined here will be added to the Tracing Depth value.
    Total Tracing Depth = Tracing Depth + Extended Tracing.
  • Clamp Level: Limits brightness of over-exposed pixels to the defined value, improving antialiasing.
    Brightness of the image will be lowered significantly when this value is less than 1.
  • Motion Blur: Enables/Disables motion blur for all animated objects in a scene.
  • Displacement: Enables/Disables displacement from all materials.
  • Volumetric Scattering: Enables/Disables Medium and SSS.
  • Relight: When on, the user can control each light separately during and after the rendering has finished.

Clay Render

All materials in the scene will be rendered as diffuse gray with respect to bump and transparency.

  • Reflectance (%): Increases/Decreases materials reflectance (from black to white)


Termination criteria are being used to stop the engine after a specific amount of time or samples.

  • Time Limit: Specifies the render time.
  • Sample Limit: Specifies the maximum number of samples.


  • Threads: Number of threads to be used while rendering.
  • Seed: Specifies the initial number for the random number generator engine. It is best to leave the default value (auto) and let the engine decide.
  • Priority: It is best to leave this to the default value (low). Low Priority does not mean low performance but is generally stable.
  • Network: None, Server: Current machine + all network nodes, Pure Server: only network nodes
  • Server Port: Should be left at the default value, except if there is any other application utilizing the select port number.
  • Bucket Rendering: Helpful for high-resolution images with additional render layers when rendering with GPUs.


A list of all the Cuda-enabled GPUs will be populated in this place, allowing you to enable or disable them one by one.

  • Device Mask: Select between GPU + CPU, GPU only, CPU only.
  • CPU Threads: Controls the CPU logical core allocation for Enhanced Thea Presto performance in both Production and Interactive rendering.
    • Auto: Automatically handled by Presto.
    • Max (-1) (-2): Removes 1 or 2 logical cores.
    • Max GPUs (-1) (-2): Removes the total number of GPUs from the total number of logical cores. -1 and -2 will remove additional logical cores.
    • 1…x: Manual logical cores selection. This section is populated based on the type of CPU.


  • Use Extended Tracing in scenes with Dielectric materials instead of increasing Tracing Depth. High Tracing Depth values will increase render time significantly.



This value controls light bounces on Diffuse surfaces as well as the tracing depth of Reflective and Refractive surfaces. Images on the left show the impact of Tracing Depth when going from 1 to 25. Higher values will increase render-time.


Extended Tracing can reduce render times a lot by keeping Tracing Depth to lower values.

First Image
Tracing Depth: 25, Render Time: 3m07s

Second Image
Tracing Depth: 5, Extended Tracing: 20, Render Time: 1m59s

In the 2nd image, there are fewer light bounces (5 times), reducing this way the render time, while Extended Tracing adds more depth for Reflections, Refractions and SSS, 25 in total.

There is, of course, a difference in brightness in the 2nd image due to less Diffuse bounces, but Reflective & Refractive surfaces will not show black areas with the help of Extended Tracing.