I have a dense scene with architecture and lots of foliage, it uses 8 GB of Vram and 9-15 GB of RAM when open in editor, and FPS is great considering the scene complexity. (RTX 3080)
Using High res screenshot I can render out great images with the path tracer using 900 samples @ 1440p or higher, and resource usage is similar to normal editor operations.
The same scene in Movie render que with similar resolution and sample’s is much heavier on RAM.
It tends to hang around 50+GB of RAM usage, and there is only 5gb “shared” vram usage spilling over from the GPU according to task manager.
Has anyone else experienced this and or does anyone know if it might be a bug or is it just the way render que works?
The path tracer looks fantastic and I am eagerly awaiting path tracing support for Volumetrics , splines and decals.
Similar problem, running 12th gen i9/3090/and 64gb ddr5 ram still my scene in slammed to a standstill renderin… anyway to make it pull from gpu or cpu?
You might have enabled in MRQ option to disable LODs and use only high resolution ones. Could you share your settings so we can see where the problem might be?
For my scene I have mostly only used LOD 0 for all foliage and trees, but I have set this in the meshes and how I imported them, not in any MRQ settings, so the foliage should be the same in the High resolution screen shot and the MRQ render.
The way the RAM increases in MRQ seems to be as the MRQ is collecting samples it is gradually filling the Ram up, leading to almost full Ram usage for 900 samples, but crashing due to running out of ram if I increase the samples.
Using EXR format seems to make the problem worse, but I haven’t compared if JPEG is better then PNG.
I am using a blueprint actor in the level to set console variables so I can swap between working lighting and rendering settings and either path or ray traced with one click.
I could open the project and post up all my console variables and settings if that would help.
my system is Ryzen 3700x, 64gb RAM and RTX 3090.
thanks,
Mike
Use both spatial and temporal sample count, and turn off path tracing denoiser in the post process.
Then if you want 1000 samples use both 32 spatial and 32 temporal samples (32*32=1024), it should do the trick. Increase the amount until you are happy with the result. You also can use Davinci Resolve to remove any noise that might appear since we disabled the denoiser, and in that case, it’s better to render 4-8 shots to use temporal denoiser.
yeah cool, I have had very good results using davinci resolve on noisy pathtraced 1440p animations with 500 samples from MRQ, but hadn’t thought to use it for stills as well.
Is it the inbuilt denoiser accumulating samples that causes the high RAM usage?
Or is there still another reason why the Movie render que is more resource heavy than the high res screenshot tool?
It would be awesome if the inbuilt pathtracer denoiser could be modified to become a post render process and have a temporal element like the resolve one.
Is it the inbuilt denoiser accumulating samples that causes the high RAM usage?
No, I don’t think it’s the denoiser’s fault, the reason I said to turn it off is that temporal samples + denoiser produce images that are smoothed, hiding all important details of surfaces, especially on faces.
Not sure why MRQ is so heavy with a high amount of samples, it’s a mystery for me as well. Before Path Tracing, I used the TAA method of anti-aliasing with 8 or so samples. It produced a great quality and really fast too, I just wish in future updates we’ll be able to use the number of samples per pixel from post process volume, not from the samples in MRQ.
I´ve turned off Denoiser in Postprocessing but GPU-RAM still gets constantly filled to maximum. Very often the editor crashes on saving the image.
Using UE 5.2.1.
