Conversion of geometry

Hi everyone,
I want to ask you for help to resolve some problems with use of external made geometry. I decided to use 3d model (old factory building) created with CAD program (Autocad) and next textured and converted to .ase file with 3ds Max (pict_01). After importing this mesh to UEd, the new StaticMesh in the Browser seems o.k. (pict_02). I've inserted this SMesh to the level - a lighting result is very ugly (pict_03). Somewhere there exist errors in the mesh (amount of tesselation? not connected vertices? overlapping edges?) . Then I converted it into Additive brush. The lighting of the brush is better but this time BSP Holes have appeared (pict_04, pict_05). Is the 6232 triangle mesh too complicated for rendering possibility of UEd ? Imho, it isn't. (The only optimization I've used it was Optimize-Modificator (3dsmax) - according with: Static Meshes: From 3DS Max 5 to Unreal Ed 3, tutorial by Gradient).
How to proceed with CAD/3dsMAX created geometry in order to achieve good result smeshes in UEd ? How to optimize it?

Thx in advance

Kantham said:

It is Because you converted the BSP into a Stastic meshe.

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Thanks for reply, Kantham.
The sequence of proceeding was exactly opposite. I've converted StaticMesh into BSP (as last step). This mesh wasn't created with UEd but with external program (CAD/3dsMax). Thanks for the link, I've read this tutorial. In the case described by AngelMapper the geometry was created with Ued originally and the tangent-line method of surface dividing is the reason of rendering artifacts. My static mesh was created with CAD / Max . I suppose that MAx doesn't apply that method of dividing particularly that 3dsMax has ability to repair that defects (according to the tutorial). Unfortunately the Author doesn't describe how to optimize correctly mesh with 3dsmax. The only tutorial I've reached (about preparing mesh and optimization), it is tutorial by Gradient: From 3DS Max 5 to Unreal Ed 3.

Hourences said:

BSP is not meant for this type of mesh, it is too complex. BSP is mostly only made up out of some cubes, your mesh is really complicated compared to some cubes.
The mesh looked bad because a. UED uses vertex light and b. I think you did not assign smooting groups, a mesh NEEDS smoothing groups.]

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Thanx for reply and your tutorial links.
You're right, the mesh is too complex to serve as BSP. Unfortunately.
During edition of the mesh with Max, I cleared all smoothing groups. This time I've checked the tip and applied smoothing group - the same bad visual effect in UEd. But that dark triangles on the statMesh in Ued suggest that some of vertices are not lit (its strange as there isn't an obstacle between SunLight and smesh ). I have to find way how to prepare such a big mesh because I've built quite a lot of different type buildings with CAD/Max and I want bring them into play.

Kantham said:

Have you Triangulated your meshe before importing it to UED?
Every single BSP vertex must be aligned on the grid so it helps to prevent that kind of mess.

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It was tesselated in the 3dsMax default manner (pict_1). I've tried to add more tesselation to all faces but it become very complicated mesh so I give up additional dividing of the geometry.
I checked aligning of BSP vertices. And much of them are outside of the grid as the mesh was prepared with different program. I have to simplify whole mesh if I want to convert it into BSP.
Thx