advice about udk
"1 Unreal Unit (UU) = 1 Centimeter (CM)
So as a working grid in Maya, you should set your grid accordingly:
Display->Grid->[Options]
Length and Width: 1024.00 units
Grid Lines every: 16.00 units
Subdivisions: 1
This will give you a grid in Maya that represents using a 16uu scale in Unreal.
I'm not sure if you are going for a level on-the-fly and want to see it in game right away or if you want to take the time and do it correctly.
You should split your maya scene into parts that can be easily "snapped" together. The reason for setting the grid appropriately is so that your meshes can vert-snap together and be aligned with the grid in Unreal. In other words, this is what we call "Modular Design".
It’s imperative that each mesh is also at the (0,0) origin while holding to the grid scale of Unreal. This allows it so rotation and scale may be adjusted later in the engine without having to go back to a 3d modeling package. As a level designer, it is extremely beneficial to use a modular design because we can swap out meshes to change the overall look of an area and also help engine performance; as well as reuse the assets in other levels.
Each mesh/part of your scene in Maya must also be unwrapped. Unfortunately, no, your bump/normal maps will not carry from Maya to Unreal automatically. You will have to manually create materials in the UDK material editor using your Diffuse, Specular & Normal maps that you used for Maya to create a material for each static mesh. Do not use black/white bump maps that you used for Maya, but a normal map. You can always convert your bump map into a normal using Nvidia's normal map filter for photoshop as a quick workaround. (yes, you can do actual bump-mapping in Unreal.. aka-> psuedo Parallax-Mapping... but thats more advanced.) You can have multiple maya materials applied to each mesh (called material slots) as long as they are properly unwrapped. Essentially, you can have multiple UV-sets on each object that will carry over. You should look on the UDN (https://udn.epicgames.com/Three/UT3ModHome) and find some basic information on materials.
Do not bother exporting your entire maya scene over as one mesh into Unreal. If its low-poly enough (like a rough-level-shell) that you would like to see in-game for scaling purposes, then thats "ok". But it will probably crash the exporter/engine because of that many verts having to be compressed. Also, the performance will be terrible as the engine has to load the entire level into memory.
Try splitting your entire maya scene into tileable or stand-alone parts with the mesh origin at 0,0."
