hdri dome noise and background

[marcoz]

Hello everyone, doing an experiment of indoor lighting with HDRI, I noticed that the dome light produces much noise that I can fix only by increasing subdivisions, around 35, so greatly increasing the time, but if used in the hdri background, render is much more clean in the same time, it is a bug, or is the normal behavior of vray?
Am I wrong or was available once the preview of the dome light?

[vlado]

The dome light might not be the best choice for interior renders - it traces rays in the brightest directions of the HDR image, but those very rarely align with the windows in the interior space that would let the light through. A combination of direct light for the sun plus a lower-range HDR for the environment might work better.

Best regards,
Vlado

[marcoz]

my experiment was inspired from a tutorial of Peter Guhtrie ,he said that he use only an hdri and the time of render is not a lot above a sky texture+sun.But i don t understand why the same image in the background seems work well without noise.

[vlado]

Do you think you can post a scene?

Best regards,
Vlado

[marcoz]

Sure, just a while.

[marcoz]

The first image was rendered with an *.exr as backgroung

follow the same image with the same hdri rotation but using a dome light with 8 subdivision

the last image was rendered increasing the subdivision the render time increase and the noise is still present, but less.

the scene is very simple but i tried with scene more complex, and for reducing the noise the time render outgrows,

consider my pc is an amd 8350@4.1 ghz, not the best of the best but decent i think

[marcoz]

here another test, with background hdri,no fireflies and very quick, in various forums I have heard that the subdivision of dome light Affect the grain but not dramatically, usually with 3dsmax vray, no fireflies just a little noise

[marcoz]

tried to set text adaptive >1 like 2 or 10 and the noise fade away