speed : preview vs. render

[protovu]

Hello Fellow BlendOctaners,

My Octane render preview is fast. With a medium complex model which is using transparent surfaces, I can snap anywhere in the timeline and regardless and get a 1.5 image with about 50 samples.

Not so when I go to do an actual render with the same settings. Very slow.

I was thinking that this might be due to mesh compilation, but the same compilation occurs in Preview Renders, yes?

How can I emulate the speed of the Preview Render in an actual animation? Frames without Denoiser about 6 seconds. With Denoiser about 14 seconds.
I must be missing something obvious.........

Thank you for the help.


Win7 64
dual xeon
32 G RAM
970,980 Ti, 2x TitanX
Nvidia Driver -4.17
StandAlone 4
Octane_Server_4.0_-_16.3
Blender_Octane_Edition_16.3_2.79
protovu
Licensed Customer

[ChrisH]

What resolution is your render and how big is your "preview window".

I think it's the resolution that is most likely to be the reason to differences in "render times"!
Usually my preview area/window is not more than 1/4 of my screen (very rarely full screen), and my final renders are from 1080, to 4K, to more...

[protovu]

Thanks for the response, Chris.

At your prompt, I just stretched out my preview to about 1920 x1080 , taking most of the secondary monitor.

The preview is still really fast. About 3 seconds.

The Render, at 1280 x 720 is about 12 seconds.

Doesn't seem to make sense, does it?

What really puzzles me: I don't see the lag from mesh compiling that I see in the actual render. After the initial compilation, the render just snaps into place as I move on the timeline.
This is what I want for test renders!

[grimm]

Short of it just being a bug, have you taken a really close look at how you are setting up the object types? If you are seeing a lot of mesh recompiles, it could be the issue.

[protovu]

Thanks, Grimm.

I am new to Blender, not to 3D. I am not sure what you mean by object types, actually. Primitives, for example?

If there is a recommendation on how to set up object types regarding mesh complement, please forward.

Even so, why would object types be a non-issue in the preview render? Same models and Keying.

[J.C]

Take a look here:
https://docs.otoy.com/BlenderH/BlenderP ... yTypes.htm

Modifiers can slow down a lot compilation time especially CPU extensive like Subdivision surface. You can apply them before rendering an animation.

As far as rendering animation in viewport is concerned I wonder too why it does compile every frame during final render while in viewport it is not.

[protovu]

Hi J.C.,
The modifiers don't seem to slow the Preview Render at all.

It is as if in the Preview Render, the file is loaded and ready, regardless of which frame I am on.

And with an animation Render, the file is being reloaded for each frame.

This sure seems wrong.
Totally slows the process.
I would be very happy with the Preview Render output for an animation.

Anyone else experiencing this difference?

I will dig into the page you referred. Thank you for that.
Rick

[J.C]

It's always been this way since beginning. This needs some clarification from the developers.

[protovu]

Is there a way to push this question up the food chain?

I see no relief from designating object types.

[J.C]

I will forward this to Lino. He is closer to developers.