number of adaptive lights

[ingoerik]

Just a quick question, if i use the default light evaluation mode adaptive lights what should i type into the number of lights field when i use one domelight for hdri-lighting and one domelight for the backround ?

[vladimir.nedev]

I don't think the number of adaptive lights matters, when it comes to dome lights.
They are handled separately with their own adaptive calculation.

But, you need to enable the Adaptive option in the V-Ray Light tab of the Dome Light, or the V-Ray GI tab if you are using Environment Importance Sampling.
Also for dome lights, make sure to enable the Dome Spherical option, by default it's disabled and only half the sphere illuminates the scene, in order to match Modo renderer behavior.

If the environment is used only as a background (visible to reflection/refraction/indirect rays is disabled), it's best to disable environment importance sampling,

Greetings,
Vladimir Nedev

[ingoerik]

So when should i use environment importance sampling, or when not (on Vray 3.6) ? I use normally one domelight with hdri for lighting and a second domelight with the same hdri for the backround (usually a bit darker), no Modo environment.

[vladimir.nedev]

no Modo environment.

In that case Environment Importance Sampling in the V-Ray GI tab of the Render item should be disabled.
There are some cases it will auto disable itself, but manually disabling it is safer.

Greetings,
Vladimir Nedev

[ingoerik]

Okay, thanks for the clarification.