Using eevee for real time rendering output


i can’t figure out how to use the power of eevee real time rendering for my purposes …
When i want to quick render some scenes, my guess was, with eevee its done really easy.
The promise that i read everywhere is, that eevee is a real time rendering engine. That works fine in the 3D viewport of blender and the results are pretty nice here.
But when i press ctrl+F12 for rendering the animation, its much slower … 1 frame each 5 seconds?
Then there is another tip: under view-> viewport render animation … thats a bit faster, but far away from real time rendering …
Even turning down the samples from 64 to 12 (viewport default) its really too slow for that purpose.
How to transfer the exact result from the viewport to an avi file with the exact rendering time (or even a bit slower which is also okay taking the writing overhead into account)?
Grabbing the screen via screencast software is not a valid solution to me.


Real-time rendering is not real-time video output. Your HDD and encoder speed is not equal to your GPU speed. And 1 frame = 5 seconds is really good result.

But is the overhead of writing that stuff to the HDD that much? I can’t believe since every screen capturing software is doing that in a fast way … i think i miss something fundamental here

Why you use screen capturing software?

That was not the question, it was just the comparison … using screen capturing software would produce fast results … why blender does not?

Screen capturing programs only take screenshot. But Eevee use GPU for render. Example, if your GPU not good for your game, screen capture program not capture good your game, produce lag on the video. The same things goes to Eevee.

Sorry but that does not answer my question … if i render eevee in viewport with a small animation with 300 frames in 10 seconds and it shows me 30fps … i could definetely start screen capturing software with 30fps, turning the 3d viewport to full screen and iam done recording that scene in 10 seconds … in fact i “recorded” 30 frames per second using that way.
If i press CTRL+F12 in eevee it takes 20-30 minutes to render the full 10 second animation result to an avi file which can be explained with advanced rendering settings like samples and so on but even with the “viewport render animation” option which should exactly represent what you see in render view its much much slower than you have in realtime on your viewport …

I mean … what is the purpose having a fast rendering enginge, if you couldn’t use the output in a fast way?

Hi Harrow. Thanks for posting your question.
Eevee : View>Render viewport is OGL capture (much like you mention a screen recording software) does the capture. In Autodesk’s language this is a “playblast”.
When you go to the top menu>RENDER> Render animation sequence, it enters the eevee engine itself to check out for it’s own parameters (motion blur, antialiasing) the path to render, denoiser, PASSES, and a long list of etc…

So appearently there is no difference, but there is if you know how OGL processes.

Ok, if this is the explanation, i have to accept. I was just wondering about that there is such a high time difference between what you can achieve when just moving through an animation with 30fps via viewport and having exactly the same output just in an avi file. That this is might be higher was something that i expected because of file writing, compression etc … but that it would be over 70 times slower is very suprising to me.
Thanks for your time and explanation anyway.

Maybe its a virus scanner that is slowing down or there are other differences for preview/final render. Check specially subdevision modifier.
For a simple rotating cube testscene in 1920x1080 my 8 old system renders (linux) nearly in realtime to hdd and ssd. So i doubt the performance drop is the output routines in blender.
Monitor memory if your system is start swapping.

Maybe my system is not the best. Running at
i5 6500
GTX 1060 6GB

Will upgrading something of this parts will help significant?

You must figure out first where the bottleneck exists.
If you render a animation with just a rotating cube, does it have that problem too?
If not then i guess you have to less memory for your scene.
Have you checked the modifieres?