value change in animation

[Armada01]

hello,

After having rendered a Rhino - Bongo animation with VRay as render engine, I noticed that while the objects are rotating, there is a change in value to the overall model while there should be none.

I first thought it might have to do with the reflections of the moving elements coming from the floor (which is a matte shadow receiver) but I placed a large rectangle behind the moving objects and the change in value is apparent on the entire rectangle, which extends way beyond the area the moving objects could affect.

Here's an example video:

https://1drv.ms/v/s!AhYoWLoGnMXWi_EP...C1J3Q?e=kmaAxg

Notice how the surfaces facing to the right ar lighting up slightly when the rotating objects are about halfway (which is halfway the video)

Anyone have an idea what might be the cause of this?

[Micha]

I have no idea what the reason for this effect is. Do you use GPU or CPU, IM/LC/BF? If you use CPU and the IM, than a screenshot of your GI settings could be interesting.