Sketchup 2020 VRay 4.0 Animation Render Times Progressively Increase

[Archway]

Hi Guys!

I am new to VRay 4.0 (having spent a while on 2.0 & about a 2 year gap in between).

I'm pleased with how easy the new interface is and have had a lot of success with static renders.

I had a go at rendering an animation over the weekend with some general success. I was rendering 1080x1080, 15 scenes at 5 second transitions for a total of 70 seconds (2100 frames).

The issue I have run into is that as the number of frames progresses, the "compiling geometry" time is increasing exponentially.

I set the animation to render at 6:00pm on a Friday night and the scenes were returning about every 1-2 minutes. Being cautious and estimating 2100 frames at 3 minutes each I expected a total render time of 12 hours, which meant it would be ready for me on my return to work Monday morning.

By Monday morning 7:30am I had only finished 740 frames and the render times have stretched out to 23 minutes (I realised it was the "compiling geometry" after watching a few more frames).

I am on a i7-7740X with a Samsung pro ssd, 64gb ram and a 1080Ti OC 11GB GPU.

System resources are not under stress during the compiling geometry phase of each frame render (GPU at 0-1%, CPU at 20%, Memory at 25%).

Any help would be greatly appreciated!

[konstantin_chaos]

Hi Archway,

The described behavior sounds strange indeed.

It is possible for the scene complexity to increase when the animation progresses causing later frames to render slower.
You can test this by activating one of the later scenes and just running a test render to compare render times.
If the render time is much shorter compared to a similar render during animation then there is something else going on.

Also, are you using displacement or V-Ray Fur in the set?
There might be something wrong with the dynamic geometry generation.

I'd also recommend you try rendering the same animation using V-Ray 5 (you can activate a trial).
If the issue is not reproducible with the latest version this will also help us in the investigation.

Konstantin

[Archway]

Thanks Konstantin,

I had to stop the animation from rendering after 5 of the 14 scene transitions as the 'compiling geometry' stage was getting too long, causing 25-minute renders. These 750 frames took 62 hours, however over half of these were completed in the first 12 hours.

I split the remaining 9 scene transitions over 3 of our machines, each a better spec than the last. Each of these machines managed to produce 450 frames in 19 hours (i7-7740X, GTX-1080ti OC), 15 hours (i7-9700K, RTX-2080ti), & 10 hours (i7-10700KF, RTX-3080 OC). There didn't appear to be any drop in frame render time in these 15-second bursts.

I will try and run the full render set on each of these three machines again over the next weekend to see if it was a one-off event, or if it was any particular machine.

"Also, are you using displacement or V-Ray Fur in the set?
There might be something wrong with the dynamic geometry generation."

- I'm not sure about any of these, I wll have to have a look through.

Upgrading to Vray 5 is the next step