Iray Server settings to maximize render performance for large format (> 2000x2000) scenes

Iray Server Admin settings to optimize performance when rendering large format scenes

Let's define a large format scene as anything greater than 2000x2000 pixels. This tip is also relevant if - in addition to have a large format scene - you also have multiple canvases.

Below you'll find two tips to maximize your render performance speed if your scene meets that definition:

1. Turn Off CPU

NOTE: Please make sure that you have properly sized your project/scene and you have selected the right GPU for optimal rendering.

Once you get your Boost for Daz private virtual server assigned, and before you start your render session, sign into Iray Server Admin. Go to the Resources tab, and scroll down. You should see:

Iray Server Admin - CPU Toggle is ON

Click on the 'Use CPU' toggle button to turn off the CPU.

Iray Server Admin - CPU Toggle is OFF

Turning the CPU off prior to rendering just isolates the rendering to the powerful GPU's and gets the CPU out of the way and should speed up the rendering time.

2. Change the preview/results Canvas Update Interval value to 2.5 hours (9000 seconds)

Most artists use a single canvas for their projects, but you can use multiple. When a large format file WITH multiple canvas is rendered with Iray Server, the Canvas Update Interval value can be a factor to consider in optimizing that experience. The reason? The large file format x number of canvas = increased update/saving times. And with a small update interval, the Iray Server will probably be constantly updating - and during this time no new upload (i.e. snapshot) can be created and added to the queue.

The default value is 8 seconds. Reviewing the definition of Canvas Update gives us a deeper sense as to why this matters:

Canvas Update Interval setting in Iray Server Admin. Default is 8 seconds.

So every 8 seconds (as a default) the renderer exports results of the active job to the disk, and this includes thumbnails and preview images as well as the results. For smaller scenes this might be ample time...but on large format renders - and multiple canvases - this can potentially lead to you experience two issues.

1. The Queue will not accept jobs while the preview/results are being updated - for small format (e.g. 900x900 etc.) you never hit this. However, for large format scenes - with the interval set to 8 seconds - a worst case scenario is that you Iray Server is always busy updating the preview/results. And no matter how many CPU cores we throw at the server, it's just too busy when fetching data from the GPUs. (At the time of this writing, this true in Iray Server 3.44 and 3.45 and we're testing Iray Server 3.50 and 3.51 but expect them to be the same.) As mentioned above, this save/update time increases with each additional canvas in your project.

2. Appears that Iray Server is stuck or crawling - It is possible that your Iray server, when set at the default of 8 seconds, will spend 8 seconds of rendering and then 20 to 300 seconds of updating the preview/results...then 8 seconds of rendering again. This make it seem like your Iray Server is stuck or crawling.

To change the Canvas Update interval value, go to the Settings tab, scroll down to the Results section:

Canvas Update Interval default value

To maximize render performance, change the Canvas Update Interval value from the default of 8 seconds to 9000 seconds (2.5 hours). Practically this means that preview/results will be saved when your job hits your iterations limit; your maximum render time limit (if set); or your convergence threshold target (render is finished).

Recommended Canvas Update Interval value of 9000 sec (2.5 hours)