Hi!
has anyone run into this issue. I have it with both CPU engine and XPU. When I have XPU set it is exactly as fast as I expect in the viewport and as far as I can tell using the same settings as render to disk or mplay. Right now I am getting my renders done by literally doing a flipbook but would love to be able to write to disk.

The only clue I have is that it seems my render times on a frame are exactly what they should be when I render to disk but it appears that I get a long delay between frames when I use the render to disk or render to mplay buttons.

thanks!

hi, it depends how much slower they are, but since mplay renders startup husk in the background, its expected to be a little slower. You can check out the "render all frames with a single process" option and see if that helps.

spektra
hi, it depends how much slower they are, but since mplay renders startup husk in the background, its expected to be a little slower. You can check out the "render all frames with a single process" option and see if that helps.

Thanks for the response spektra! so I forgot to mention that I did that "render all frames with a single process" and it appears if the render goes at the desired speed ( progress bar is done as expected ). Yet when I check the render scheduler the process is still going and takes another 30min to finish. If I review the folder on disk I can see frames being slowly put into the folder. the behavior is.... weird.

caden
Thanks for the response spektra! so I forgot to mention that I did that "render all frames with a single process" and it appears if the render goes at the desired speed ( progress bar is done as expected )

It still has to render the images. The progress bar is complete when the stage has completed exporting in single process mode. This could take a few seconds or be almost instant depending on how much has to process in the scene. Once husk is launched in the background, it still has to render the frames which won't be instant.

What speed are you expecting for each frame?

Sorry for the delayed response. I think I may have gotten to the bottom of my issue.

First to answer your question jsmack, I am expecting 3 seconds per frame and instead getting 30 seconds per frame.

I think that what is happening is that when I have karma set to XPU and try to render headless the issue becomes hidden. I think that what is happening is that without having "render all frames with a single process" checked Karma automatically defaults to a CPU render when hitting render to disk. That said, if you click "render all frames with a single process" houdini only tracks the the usd export and the render is just going in the background. This makes it hard to decern per frame times but once I did the math render times where as expected....

looking forward to karma xpu being moved out of alpha thanks for all your help!!

caden
I think that what is happening is that without having "render all frames with a single process" checked Karma automatically defaults to a CPU render when hitting render to disk.

No, but it will open each usd file as a separate frame, render the image and then exit when done. This start and spin down process probably takes much longer than rendering a frame. That's why render all frames in a single process is much faster. There is also the usd export time on the Houdini side. By default, each frame is saved as a single usd file and rendered before moving on to the next frame. This allows sloppy scene authoring and animating properties that cannot be animated in USD. This is why it is the default. If you notice when enabling XPU, the Optix device will say 'init' for quite some time while the image first starts rendering in the viewport. This is how long it takes for the nvidia rendering library to load and for the assets to be transferred to the GPU. For me it takes about 30 seconds. This could be a large part of the time between frames when rendering frame by frame instead of all frames at once.

Try rendering something that takes more than a few seconds to render, then the start up time won't matter as much.