I'm rendering a huge amount of polys. Don't know the number exactly but were talking thousands of animated characters (with a level of detail setup luckily).

However, some random frames take perhaps 10x as long to render as the frame before and after. It's like one of the buckets is getting stuck in the render. Does anyone know what the issue might be and how to solve it? Or decrease the render times.

I'm using micropolygon rendering with an area light with 16 samples, and a spotlight, raytraced shadows om both, motion blur, and a quite simple shader, no SSS/displacement or similar. So apart from the high poly count it shouldn't be that heavy to render.

If you put verbose on 4 for the renderer, then see if you can identify the location of the bucket that is “stalling”. Then check to see if there is a specular highlight that is crossing two buckets. I've seen renderers stall in that condition.

probbins
If you put verbose on 4 for the renderer, then see if you can identify the location of the bucket that is “stalling”. Then check to see if there is a specular highlight that is crossing two buckets. I've seen renderers stall in that condition.

I don't think that is the problem. All the instances have some specular and the speculars are very small. When rendering to mplay I'm able to see which bucket it is and its always a bucket with dense geometry. But there are lots of dense geometry in other buckets and on all other frames as well. It seems quite random.

Maybe you could try rendering the ‘How long did this bucket take’ pass.

In the Mantra Node Arbs, you can add a ‘Diagnostic: Render Time’ layer.

It might provided some clues for you.


cheers,
-j