Massive IES problem

Hi guys. This one's got me more stumped than ever.

I have a scene (many rooms) with two types of light. square ceiling lights and wall-washers.

I attach two images below. [with.jpg] is rendered with the other Vray IES lights (square) in other rooms in the scene. As you can see, having other lights in the scene is weirdly making my wall-washers dim and flat.

[without.jpg] is when only the wall-washers are in the scene. Looks, you'll agree, correct.

Also, the more square lights I unhide from the scene, the less bright the wallwashers get (????)

No idea what to do. Thanks for advice in advance.

I don't believe the issue is that unusual and in fact it's acting just like it would in reality - wall washers will take on less of a presence with other lights on! Try a quick experiment. Take all the other lights in the scene and exclude that veneer wall. In that way you should get closer to what you want. You may have to then set a special rectangular light that also only shines on that veneer wall, but is turned down pretty low to just give some very basic illumination. I often have to fudge things like this when using IES lights.

do you have automatic exposure control active by any chance?

Hi, thanks for all your responses - response from Chaos Group below;

#Hello,

Thank you for contacting us.

This is because Probabilistic Lights, a new feature we have in version 3 : http://docs.chaosgroup.com/display/VRAY3/Global+Switches#GlobalSwitches-Example:ProbabilisticLights

If you turn this off your lights will be rendered just fine.#

Nice new feature defaulted to on!

SOLVED.

Ha! that's great. Thanks for replying with a solution. Few actually do that.