OTOY Forums

Hi!

This might be a complete newbie question, but I'm seeing some curious behaviour with the modo 901 plug-in.

In a scene I'm working on, when I render a single frame in octane viewport, my MSamples per second brake 9.00 (preview mode is off). But when I render the same frame with same settings, but inside an animation render, MSamples are stuck below 6.50.

I've tried with or without render passes & different file formats (exr vs png). The MSamples always stay below 6.50 when rendering animation. But as soon as I go to the normal viewport render, MSamples bounce back to 9.

So far all the scenes I've rendered as animation show similar behaviour. Is this normal?

Or is there a setting I don't know about? I've tried to find something in the manual. No luck so far. I just might be blind.

Help would be much appreciated, since the hit in render times is significant.

System:
1×Gtx 980 ti + 1×Gtx 970
Windows 10
Modo 901, service pack 3

My apologies for the late reply to your question - I somehow missed this post.

Firstly, you would need to compare the same frame number when rendering the animation verses a single frame, since you will get different render speeds for different camera positions.

Secondly, you may have motion blur enabled when rendering the animation, which may slow down the samples per second.

Thirdly, there is currently a plugin issue I am investigating where the Octane camera position is very slightly different when rendering a specific frame in isolation, verses rendering it in an animation. I hope to get to the bottom of the problem in the next few days.

Paul

Hi Paul!

Thanks very much for the reply! This has been driving me mad. The renders are still amazingly fast, but when even faster results seem to possible... You know how it is. One gets obsessed trying to find that one box or setting that might be causing all the trouble.

I tested the difference now with my latest scene. All my tests are done within the same project. I haven't tested yet with a completely different project that has different assets and texture maps. I'll let you know when I have time to do that.

Still frame in Octane viewport (not in preview mode) - up to 11 MSamples per second.
Same frame as first frame of animation - up to 8.9 MSamples per second.

1) I can confirm that I'm doing the tests with the same frame
2) In the Octane Kernel settings I've got my Shutter Speed (ms) set to 0, so no motion blur (right?)
3) Would that very slight difference in camera position when rendering animation result in such a dramatic drop in MSamples?

So I don't know what it could be. Does anyone else experience the same issue?

2) In the Octane Kernel settings I've got my Shutter Speed (ms) set to 0, so no motion blur (right?)

Correct

3) Would that very slight difference in camera position when rendering animation result in such a dramatic drop in MSamples?

I doubt it - the camera position difference is microscopic.

I just did some tests - and found rendering animations was running about 2% slower than a single frame. I doubt have an explanation for that - sorry.

Paul

I have now worked out the reason for the speed difference. Pls see the second "IMPORTANT" note at https://docs.otoy.com/Modo/?page_id=998 for an explanation.

Paul

Thanks a lot Paul. I guess I should read something marked as IMPORTANT better next time, when I try and find answers in a manual. Thanks for finding it!

Now I'll try and see what tweaks I can make to speed up the renders.

Cheers & thanks for a great plugin!