Why is my render taking so long?

Are you seeing looping render iterations in your DS logs? You may have run into an Iray Server bug. Here's what you can do...

We are working directly with the NVIDIA Iray Server team to validate and resolve this issue (resolution time is unclear at the moment), but fact is that there is a bug that occasionally pops up its ugly head - unpredictably - for jobs that are submitted to the Iray Server queue of any size, but probably for jobs near or over 4megapixel (2000x2000)

Issue Explained

Your instincts as a Daz artist are well honed to when you feel that a 'render should be done by now'. That's important to acknowledge and appreciate.

So when you sense that a renders appear to be taking longer than it needs to, you check in the logs and see that the render seems to be stuck at a specific iteration and keeps resetting back to iteration 1.

The essence of this issue lies in a Iray Server parameter called Canvas Update Interval. This value tells Iray Server how often to write the results of the active render job to disk. This bug manifests itself when Iray Server starts the render process over again at the canvas update interval.

This is the reason why your render is taking long. It's stuck in loop...and its wasting your time and money. So how do you reduce the chances of this happening to you? That's next.

Solution Explained

The Iray Server parameter called Canvas Update Interval can be viewed and changed through the Setting page in the Iray Server Admin application. You can learn more about accessing and using Iray Server Admin here.

The default canvas update interval for Iray Server is set by NVIDIA to 8 seconds but that might not be enough for these larger projects.

Follow these steps to effectively prevent the chances of this happening to you:

Step 1 - Fine Tune Convergence and Max Iteration Values

Do some fine tuning that can help reduce the render burden and duration for your project. Based on what we've seen in advising many established Daz artists, we recommend taking a good, hard look at your Convergence and Maximum Iterations values.

As you know, your render will (technically) be complete when either one of these values in reached first - either Convergence or Maximum Iterations.

Many Boost for Daz customers feel that .95 convergence is overkill, and recommend that most should target .85 for still images and .70 for animation frames.

Then consider if its possible to reach that Convergence level is less iterations. Pick the minimum Max Iterations value that you feel will get you the desired Convergence level. If not, change and render it again. (You will not have to upload any Daz files after the initial upload, so any subsequent renders happen are completed quicky).

Setting the minimum viable Convergence and Max Iterations values will help optimize the time, expense and quality of your renders.

Step 2 - Pick the RIGHT GPU for your specific project

Be sure to choose a GPU (or set of GPUs) that can get the job done in that time frame. The trick is in ensuring that your project fits entirely into the VRAM with some (acceptable) room to spare. Learn how to roughly size and pick for the right GPU for your project.

Step 3 - Change the Canvas Update Interval value

Change the Canvas Update Interval to 9000 seconds (=2.5 hours) prior to starting the queue. Learn how to configure Iray Server Admin for large project sizes.