Help needed with Global Illumination

[Blaine]

Hi,
The light from outside leak into my house in corners, I am using the default GI settings with no FG and the scene is lit with a Daylight System. The house walls are an AEC Wall and the ground is a plane and the roof is made of two intersecting boxes. I want help to stop the light sneaking through my house in corners.
Thanks in advance.

[CADTomato]

Hi,
In your GI Settings , I hope you are using mental ray, Turn maximum sampling radius, and set it lower. The radius it's sampling is to large and so the light is bleeding through, if you set it smaller it shoudlnt' go through the edges.
Or
You could also attach the floor, the walls and the roof to one poly mesh and weld the vertices's, so you kinda make those edges or intersections "water proof"... that way light should not go through.
Cheers!