Blackmagic Forum

Help me please advice. In the process of studying Fusion, I faced a problem with settings the final rendering. More precisely, with very slow rendering the final video.
I decided to create a scene using 3D models of buildings and created a clouds, using node Volumetric Fog of Fusion.
I was puzzled by the fact that the Preview render is fast - about 2.5 frames per second. But the Final render thinks about 5-10 minutes 1 frame!!! But at the same time, the quality of Anti-Aliasing image is very mediocre. And for some reason, during the Final rendering is never used the processor, but very active hard drive.
Please tell me how to set up the render?

Try using GPU render and not software. All the volume tools use the GPU.
Make sure you select the 'ss' option for the RGBA channel (super sampling)

As for the view, if you have it set to 'fast' then it using a simple z-sorting system that is pretty fast compared to final render.
In the GPU render settings, you can also choose between z-buffer, sorted, accurate modes. Each one will result in different quality/speeds.

Now that answers your question about settings, but the real problem is going to be in your setup, as I have never really seen any comp that takes that long. I'm pretty sure you can make it more efficient if you play around with it.

In my case, the problem is very slow rendering, was a Bump map, which was applied for the 3d buildings. Disabling the Bump maps, dozens of times increased speed of the final rendering.

But also there is a problem with Anti-Aliasing image (for example in the attached picture). I tried to use OpenGL Renderer and Software Renderer, but the jugged (staircase) on the image, I could not get rid of.

Does this aliasing effect happen when you apply the volume fog tool?

You could try rendering an anti-aliased world position pass (using the OpenGL renderer + "SS" checkbox).

If that doesn't help, there's always the old trick of rendering at twice the resolution and scaling everything down in the end.

Yes, the smoothing effect is not working on the Volume Fog tool.
Unfortunately, your advice - "rendering an anti-aliased world position pass (using the OpenGL renderer + "SS" checkbox)" - not given any results.

I think there's another checkbox you need to enable on the Renderer3D... something with subsampling or supersampling (which works in HiQ mode only). Sorry, not in front of Fu right now

These checkboxes are selected by default. Therefore, this version I have also tried. But it did not give any result.

Make sure HQ is on. The SS of openGL is limited to HQ mode in the comp (next to the play controls)

Indeed the "HiQ" function has been disabled. ...Unfortunately, the ON of this function is also to no avail. And when the "HiQ" is ON, Saver becomes is red.
Maybe I just do not correctly assembled composition, and therefore Volume Fog does not interact with 3D objects. (You may have noticed that in addition to jugged on the brink of Fog and Buildings, there contour with empty pixels)
I am attaching an example of a scene, maybe it will make it possible to understand the problem.

Usually final render does automagically turn on HiQ. That explains the longer render times.
I do not now your specs but my guess is that with all the supersampling in HiQ the graphics card is not capable to render the scene anymore (VRAM?).

Is it specifically the Saver that turns red? What does the console say?

EDIT: You might try to set the renderer to 8 bit, if that is ok with your downstream processing.
Or set the input textures to 3D to 8 bit. Floating point textures are not the cheapest and I guess that this could affect the setup.

As I said before, with the speed of rendering, I already understood. Final render very slowed Bump map, if it is turned OFF rendering speed has increased tenfold!

Now, it remains a problem with anti-aliasing. I am a novice in Fusion and could not find a solution to this problem, using the proposed methods. That's why I posted the test scene. Maybe someone from the forum participants will be able to see test file and suggest a solution.

See the attached comp.
Changes I made:

1. Do not use an imageplane. it will cause more antialiasing that will again be sampled when loaded as texture. Also this makes worse volume for integration.

2. I enabled SS in the RGBA pass as well.

3. Although 1. helped there still is small fringe after the Volume tool. WPP is a cheat, so cheat! I rendered everything in double the resolution and then scaled back at the end. Enable the GREEN tools to see it. You could also try to enlarge the image, of soften the edge with a separate alpha.

4. I've send in the cleaning lady into your comp