This page provides information on distributed rendering (DR).


Overview

Distributed Rendering is a technique intended to speed up rendering by dividing the rendered image into individual regions (buckets). Each machine on the network is then given a number of regions to render, and the machine that started the process gets the results and combines them into the final image.

In contrast to a regular "Render Farm" where the rendering process is sped up by utilizing multiple render nodes to render multiple animation frames in parallel, Distributed Rendering is used to speed up the rendering of a single frame.

V-Ray uses the following convention to refer to the render nodes on the network:

  • Render Client – the artist workstation / computer from which the rendering is started. It divides the frame into rendering regions and spreads it across the network. It distributes data for processing and collects the results.
  • Render Server – one of the nodes on the network that does the rendering work. A Render Server requests render data from the Render Client, processes it, and sends the result back. If any of the servers fail, you will get a notification and the Render Client will try to reassign the buckets to another server.

Every Render Client requires a Render Node license. To see how to set up your render license, see the Licensing page.


Setup


Render Servers:

  1. Navigate either to the V-Ray for Houdini installation folder, or the V-Ray Standalone installation folder.
  2. Navigate to the "appsdk/bin" folder if using V-Ray for Houdini, or the "bin" folder if using V-Ray Standalone.
  3. Open a new Command Prompt/Terminal and call "vray.exe -server" to start V-Ray in Server Mode.

 The default V-Ray installation paths are:

  • Windows: "C:\Program Files\Chaos\V-Ray"
  • Linux: "/usr/Chaos/V-Ray"
  • OSX:  "/Applications/Chaos/V-Ray/"



Render Client:

  1. Inside Houdini, create a V-Ray Renderer and go to Renderer → DR.
  2. Select Enable and add the Render Servers' network addresses. You may also want to disable "Use Local Machine" so that rendering is not performed on the Client machine.




It is crucial to ensure the V-Ray Core Version is the same across all Render Servers and the Render Client. An easy way to check is by using the V-Ray DR Check tool.

  1. Navigate either to the V-Ray for Houdini installation folder, or the V-Ray Standalone installation folder.
  2. Navigate to the "appsdk/bin" folder if using V-Ray for Houdini, or the "bin" folder if using V-Ray Standalone.
  3. Open a new Command Prompt/Terminal and call "vraydr_check.exe -host=(HOST_ADDRESS) -port=(PORT_NUMBER)". For example: "vraydr_check.exe -host=127.0.0.1 -port=20207".

The following information is returned:

  • Status:ready
  • Num processors:12
  • V-Ray core version:5.10.20
  • V-Ray revision info: Jun 4 2021 13:28:51



When rendering with V-Ray GPU, you may want to specify the devices on the Render Server machines used for GPU rendering.

To do so:

  1. Navigate either to the V-Ray for Houdini installation folder, or the V-Ray Standalone installation folder.
  2. Navigate to the "appsdk/bin" folder if using V-Ray for Houdini, or the "bin" folder if using V-Ray Standalone.
  3. Open a new Command Prompt/Terminal and call "vray_gpu_device_select.exe". This opens a new window listing all CUDA/RTX compatible devices on your machine. Select the devices to use for rendering and hit the Set devices button.

The V-Ray Render Server has to be restarted for any changes to take effect.





  • If the VRAY_ASSETS_CACHE_PATH environment variable is not set, the default system Temp folder is used for copying the assets, usually  C:\Users\<username>\AppData\Local\Temp on Windows (%TEMP%) or /tmp on Linux and macOS X ($TMPDIR).

  • When you cancel a DR rendering, it might take some time for the render servers to finish working and they might not be immediately available for another render.

  • Servers can be added, removed, enabled, and disabled while running a CPU distributed render. When using progressive rendering, nodes can only be added or enabled while rendering. While rendering, some of the options are disabled. Stop the render to make adjustments.

  • For GPU rendering, DR settings can not be changed during the render.

  • For versions prior to V-Ray 7, the default installation paths are:

    • Windows: "C:\Program Files\Chaos Group\V-Ray"

    • Linux: "/usr/ChaosGroup/V-Ray"

    • OSX:  "/Applications/ChaosGroup/V-Ray/"