Strange Exterior Lighting

okay, I’m building a room for a movie and it’s supposed to be nighttime. So I have a dim light right outside the window.
Later in the movie, a new blue light appears, so I put it outside of the room. I rendered the first frame to see how the room was looking and the blue light seemed to be shining right through the solid walls. I even tried sticking the light in a solid cube.
Help with modeling of the room is welcome.
I would also like instruction on how to change something’s material in the middle of an animation.
with blue light:

with no light:

link to download blendfile:

Kroni has written a very nice tutorial on lighting - you can find it here. Your lamp is a Sun which is used for general and thus overall lighting…

This thread should help you - it’s not the only way, so try use the search function :eyebrowlift:

From the looks of it, you did not enable shadows for the light, that’s is why it’s shining through everything. But enabling shadow would give you another problem: your room is a box, and therefore not much light can enter the room.

Instead of using lights, tryAmbient occlusion, it’s a far more elegant solution.