Artifacts with HDRI in the Env slot

[fAEkE]

When we are using HDRI in the vray environment override slot we get alot of artifacts. It looks like an extreme amount of noise. It can be fixed be putting the HDRI in a dome light, but since dome light needs a huge amount of subdivs to render a noisefree image it's not an option.

Can anyone explain why the result is so different when using dome or env slot, and if there is some way to fix this?

I apologize if the subjects has been discussed before, but I'm working on a tight schedule and don't have time to search/read atm.

[instinct]

The Domelight automatically downsizes the Map according to the resolution settings. So in comparison the map used can be quite a lot bigger when in the environment slot.
More detail = more artifacts roughly spoken hehe

Regards,
Thorsten

[fAEkE]

Oh, But I also tried to use a 2000 pix 8 bit jpeg for the env slot (of the same HDR ofc) and it gave the same artifacts.

Thanks for the fast reply, I'll see if I can test some more with lower res env maps.

[prateekvishwa]

is it possible to post some render to see wht exactly is coming in thr?

[fAEkE]

Yes, I had some time over before lunch to render a couple of tests, and while doing so I accidentally stumbled upon the solution..

First image is with Dome light. Second is with the HDRI in Env and Irr map as primary bounce. Third is with the HDRI in Env and Brute force as primary Bounce. I guess I need a serious amount of brute force subdivs with HDRI env to sample a noisefree image.

[rivoli]

I guess I need a serious amount of brute force subdivs with HDRI env to sample a noisefree image.

the dome light does importance sampling with textures, it helps clearing noise in a more efficient way than what you get from the same map in the environment slot.
at the end of the day you may end up with faster render times sticking with the dome light.

[fAEkE]

Hmm, my experience is that you need too much subdivs for the dome to get good quality. Seems to me like an image for Env is pretty noiseless when using Irr map. Yes I'll probably loose some detail, but env is often used for overall lighting and don't have to bring forth detail in the image.

I'm testing full res (A3) renders now and I get much smoother resault without the dome and much better rendertime.

[prateekvishwa]

i guess increasing irr hemispherical sub div in 'Env_IrrMap.jpg' setup shd help. may be 100+

[vlado]

Might be better to go with a dome light in this case.

Best regards,
Vlado