Forget the last post. Somehow I turn off light features in the viewport
Mods, pls make instruction to lightmap uvw and stick it as first thread in red.
I dont know much about 3ds max, lightmaps or any technical stuff, but I ran into a similar issue during one of my first projects with Unreal4.
Im not sure if this will help, but I found out that a few of my static meshes were black on my map. I managed to fix it by changing the lights nearby that were supposed to light the room, from Static lights to Stationary lights instead. Then they lit properly.
I’m a technical newbie with unreal, but I hope this helps.
~Engi
As has been mentioned there is a wealth of information out there regarding UVing in max, but as I’m at a loose end I’ll give you some steps.
This is assuming you have already unwrapped your model for the base material (UV channel 1 in max which is treated as UV channel 0 in UE4). If you have no UVs at all then you need to go and research the basics.
- Apply an Unwrap UVW modifier to your model
- Set the Map Channel to 2 (UE4 and code in general will treat this as UV channel 1)
- Hit Reset UVWs (i’ll explain why below)
- Edit the UVs to have unique space for all faces
The reason I said to hit Reset UVs is so that you can see how the 2 channels differ. Missing this step will copy any existing UVs to every channel you switch to.
This is good to start with as chances are you have a uniquely unwrapped model, and you can add the modifier, change to Map Channel 2 and then edit. This will copy channel 1 (which max will default to in the modifier) to channel 2. With the UV editor open, enter face selection mode and then go to Select > Selected Overlapped Faces.
If no faces are selected when you do this, then you have no overlaps and you should be good to go with the lightmaps in UE4. If you do have overlaps then fix these and collapse the modifier.
So, in this next example, you have copied your UV1 to UV2 and had to make edits because of overlaps, exported to UE4, but it’s complaining that there isn’t enough space between UV islands.
When you come back to max to fix this and add a new UVW modifier, you want to avoid copying UV channel 1 to UV channel 2, because you will lose your previous edits. In this case then the Reset UVWs step is essential. It will mean that you are editing whatever channel the modifier is set to, BUT you have reset to the UVs that existed before adding a new modifier, in other words preserving the work you did initially.
An extension of this would be if you have more than 2 UV sets for different purposes (a game I’ve just worked on required 6 channels on terrain that defined all manner of things such as base texturing, lightmaps, detail mapping, physics properties, and more). If I wanted to edit channel 4 and added an Unwrap UVW modifier, then used the arrow buttons to move from UV channel 1 up to UV channel 4 WITHOUT hitting Reset UVWs, then I would have overwritten channels 2 3 and 4 with the UVs in channel 1 - i.e. I’d break A LOT of things. So there I’d hit Reset and make any edits necessary.
“But what about wanting to copy channel 2 to channel 6 without messing everything up in between?”, I hear nobody cry 
Well, in that case I would add the Unwrap UVW modifier and change the channel from 1 to 2 and hit reset, because I don’t want to make any changes to those channels. Next I would TYPE ‘6’ into the Map Channel and NOT use the arrow buttons, therefore skipping over channels 3 4 and 5, but still copying 2 to 6 as desired.
Hope that helps 
major things are here http://www.worldofleveldesign.com/categories/udk/udk-lightmaps-03-how-to-fix-light-shadow-lightmap-bleeds-and-seams.php
remeber about
- create second channel for UV
a) UV cannot overlap
b) has to be inside 0,1 box
c) ALWAYS should be snaped to resolution grid (create a background checker 64x64 in photoshop, and set it in background in UV editor - and add snap to background)
d) 64 resolution is enough
2)Weld UV’s where you want continuous lighting. Split the UVs where there will be a break in lighting. Such as a turning corner or top of the object.
Keep faces that change direction and will cause light/shadow change as separate UV shell.
- You must have padding to prevent lighting/shadow bleeds across your model around every UVs shell. 2px is good, sometimes it will require 4px.