Page 1 of 1
volume glare postprocessing spikes
Posted: Fri Jun 27, 2025 12:32 pm
by marcikola
Hi!
I have random spikes on the glare i add in the postprocessing tab when rendering volumes, please see the attached video.
I think its random, sometimes its on one frame, then on another, cant reproduce always reproduce it.
Using Octane 2025.1.2.0 and Houdini 20.5.487
Re: volume glare postprocessing spikes
Posted: Sat Jun 28, 2025 12:41 pm
by skientia
Without access to the video (as it forcefully require to be downloaded), and as a generic information: the PostFX will "overly react" to the most emissive pixels; at low samples
"hot pixels" / "fireflies" can occur in more areas than at high-enough samples and if remaining,
several optimization methods are effectively applicable.
Could it be the reason?
When it comes to volume, in some situations the volume is
more prone to these.
Perhaps, the
Phase (scattering direction) is pushed too negatively?
Re: volume glare postprocessing spikes
Posted: Tue Jul 15, 2025 2:48 am
by dom_otoy
skientia wrote: Sat Jun 28, 2025 12:41 pm
Without access to the video (as it forcefully require to be downloaded), and as a generic information: the PostFX will "overly react" to the most emissive pixels; at low samples
"hot pixels" / "fireflies" can occur in more areas than at high-enough samples and if remaining,
several optimization methods are effectively applicable.
Could it be the reason?
When it comes to volume, in some situations the volume is
more prone to these.
Perhaps, the
Phase (scattering direction) is pushed too negatively?
Yeah I agree. I think you probably have some hotpixels that are triggering the glares.
You could try using the remove fireflies slider, or lowering the GI clamp.