Hi,

This might be a daft question, but I'm starting to look into render optimisations and techniques with Karma and I was wondering if you could visualise an image's pixel variance as an AOV? Both because the pixel oracle uses it for it's adaptivity and as a kind of pre-denoise check.

I guess you can kind of see areas where it's high based on the primary samples AOV if the oracle's clamping the low variance areas, but I was wondering if there was any way to pull that variance value out in the same way the primary samples / CPU time etc are in the "optimisation" setup? I've had a look through the log and can find the different stats for the other optimsation AOVs but can't find anything I could use to pull that pixel variance out.

Cheers,
Paddy

Bumping this,
this is a pretty useful feature for implementing denoisers.

Was able to create variance aov with a custom render var, so here it is (my lights are all prefixed L0??) :

Format: color3f
DataType: color3f
SourceName : C.*[LO]
SourceType: LPE
PixelFilter: ["stats",{"mode":"var"}]