Big White Blotches when using self-illuminated material

[Dave Buckley]

Taker a look at the two attached renders, the setup is, 1 free area light, FG and log. exposure contol. The free area light is placed jus outside of the room. The white blotches appear when i place a self illuminated box in front of the area light. the render without the blotches is after deleting the self illuminated box. However, i need the box there so that i can get a glare from the cross shape in the wall, i want it to look like the sun outside is extremely bright, and i also need great contrast between interior and exterior,

 

the building is of course inspired by the church of light by who else but, tadao ando

[Justin Hunt]

For this scene , dont use self illumination, but rather a mrsun and sky setup with Photons and FG.

 

I am guessing that there is already enough light entering and bouncing around the room to give you what you want, but your exposure control settings aren't high enough to show it

 

JHV