I have a set of static meshes which are used as part of a modular building system. Each panel is 400 units across and 400 units high. To make a wall, you just stack them next to each other. Unfortunately, this technique is having trouble with the lighting. Here is a sample screenshot:
You can see clearly see the boundaries of each mesh instead of having a smooth gradient across the span. In this example, the level is just a simple box room with a single point light in the center.
The static meshes have UV coords for both texture and the light map. Checking the lightmap density in the editor doesn’t show any problems. (You may also notice the ceiling, which is a BSP brush, has a smooth gradient as desired. So the problem seems to have something to do with using static meshes.) The material used for the wall doesn’t use UV mapping, so I don’t think it’s a material problem.