The obvious choice would be to change your lighting from infinite lights to spots or point lights. That way, you can place them at a specific point in the 3d space, within the walls you have constructed. Infinite lights are only really worth using if you're trying to achieve an outdoor lighting look, where the light source (eg: the sun) is so far away, and give out so much light, that allocating it a specific point is redundant. For other uses, such as studio lighting or interiors with walls and ceilings, infinte lights just don't work. Of course, if you're determined to use the infinite lights, then going to your walls, clicking on the 'properties' tab, and deselcting 'casts shadows' will also knock them out of the game. Hope this is of use to you. Jonthecelt