There seems to be something fundamentally different about how the Path Tracer in Movie Render Queue works compared to taking a HighResShot in the editor with r.HighResScreenshotDelay to accumulate the samples.
I am able to produce 4k stills of my scene at 2048 samples with the memory on my 4090 not going above 40%. I can even use screen percentage at 150% to get really nice crisp images.
If I use the Movie Render Queue to try and do a 1080p render of the same scene with the spatial samples set to 2048 and 1 temporal, it starts going then crashes with the “Out of video memory trying to allocate a rendering resource” message.
I can see in the command prompt window that its saying the message “Creating RT Sampler Heap with 2048 entries” and “Creating RT View Heap with 250000 entries” on every tick, filling up the memory then crashing when its full. In the editor this message only appears once when you load the level. Activating the path tracer does not cause any more of this message.
Because the message says RT I have tried r.RayTracing.ForceAllRayTracingEffects 0 in MRQ but it hasn’t helped. I have also tried tick boxes in the Path Tracer Section like Reference Motion Blur, Disable Multisample Effects. I have also disabled all game overrides.
There is no landscape or foliage in my scene: its a car with a HDRI environment.
My scene is in 5.3.2 but I have had this same issue in all the versions since Path Tracer was introduced. I’ve been getting by with the HighResShot but I cannot do any animation or motion blurred still with this.
I’d love to know if this is a bug or I’m just using Movie Render Queue wrong!
