Manually reset path tracer sampling

Hi. We are implementing a system to record customized animated characters in runtime using the path tracer but have noticed some oddities. It seems to start sampling when things in the scene change like for example camera movements or when manually evaluating a time change in a timeline. For the last case though, it seems to reset one frame prior to the actual timeline frame change making it sample the previous timeline frame once, creating a ghosting effect in the final converged frame.

This can be easily avoided by resetting the path tracer sampling. But for now I’m “solving” it by moving the camera slightly on the update after changing the timeline frame.

mid there is no actual method to force it to reset sampling, I’d love to know what else can trigger a sampling reset, other than moving the camera. Any pointers are appreciated.

 

Sure. I’ll open a ticket. Strangely enough it does not happen on 2020 but it does on the latest 2021.

 

It would be fabulous to make it public as there might be use cases where you want to make certain that the path tracer accumulation is cleared.

 

Hi. case number is 1126233

 

I also reported on that ticket an issue on the test project where path tracing will remain stuck on startup for nearly 10s on 2021.2.0, but start automatically on 2020.3.21. I attached videos and sample projects.

 

That is an enterprise support ticket (I'm with Jam City). I'll PM the zendesk link.

 

Excellent! I'm currently using Package Manager to access HDRP. Is the source version from Github compatible with unity 2020.3.21 or 2021.2.0?

 

Thanks. will do that!

 

Hi,

in my archviz projects I have a functionality to save (hig-res) screenshots using rendertexture.
In the past years I used builtin-pipeline and everything was easy.

When I switched to HDRP with raytracing I realized that my screenshots looked fuzzy and I now had to converge the screenshot across multiple frames before saving.
Customizing the provided FrameManager.cs I am now able to save highres and sharp images.
Also it was easy to implement a simple progressbar (m_Iteration / samples).

Now I want to do the same with a pathtraced image and here I have a problem with my progressbar:

It looks to me that the pathtracing-process is kind of an internal process with no public API.
PrepareSubFrameCallBack etc is called internal and therefore getting the current frame is not possible.

So instead of starting the pathtracing accumulation process by code (don´t know how, missing examplescript!) I simply enable the volumeoverride with "pathtracing.enable.value = true;"

In the same frame I enable a bool named "pathtracerRunning" which allows a counter in the Updateloop to calculate the progress:

Code (CSharp):

1. void Update()
2. {
3.    if(pathtracerRunning)
4.   {
5.       frame ++;
6.       progress = (float)frame / (float)samples;
7.       progressslider.value = progress;
8.   }
9. }

The comprehensible problem is that this counter is not in sync with the real accumulation-process of the pathtracer.

What I would need is a method like "HDRenderPipeline.currentIteration" or even better "HDRenderPipeline.progress".

Can anyone help me here?

 

Not fully.
The documentation scripts presume that the pathtracer is already enabled - right?
At least I don´t see any code that activates it.

In my case my app starts with no pathtracer active.
Then I have a toggle or button that activates pathtracer.

The problem is after enabling the volumeoverride ("pathtracing.enable.value = true;") it automatically starts processing the image. This makes it impossible to run the code from the docs which would cause a second parallel accumulation.
I have no access to the current frame / sample and therefore I can´t calculate the progress.
(We only get this semi transparent progressbar on the bottom with no access for customizing it).

I need something like Pathtracer.Start(), Pathtracer.Stop(), Pathtracer.Reset() and Pathtracer.progress.

 

Another issue I have, although it maybe not the best place to post it here:

While accululating my final screenshot I display the current state of the accumulation in a rendertexture using a rawimage.
A 4k rendertexture allocates ~4GB of VideoRAM (works fine: shot takes 3 seconds) but an 8K Rendertexture completely slows down the rendering process (takes several minutes) allocating ~16GB on my 8GB graphicscard:



My question is if there´s a more efficient way to display and save a highres accumulated screenshot.

Thank you!