Hello,
In Startrooper, I see unique lightmap for all objects.
But 3DsMax make 1 lightmap for one object. How could I make 1 lightmap for all object.
Thank in advance.
Join all your objects together into one mesh, then generate a lightmap for that object.
There’s a few ways…
You can either attatch all the objects together to make one big object, and unwrap their channel 2 all onto the one texture split them apart again once you’re done.
What I did for affirmation garden was much simpler, I would unwrap one object into roughly a quarter of a texture, bake. Then, I’d unwrap another into the top right of the same texture, repeat… Until i was physically out of space.
I ran into some problems with the scaling of textures, I was originally rendering everything at double size and scaling down, but this caused edge issues so eventually I was rendering out at 1 to 1.
Here’s a UV, several objects were combined to save on draw calls, but in Max they were all seperate objects until it came to exporting into the fbx format.
This is all basic max stuff, its pretty well covered in the tuts that come with it (even though some of them are over a decade old now… lol)
The key is lowering draw calls… I found polys weren’t the killer at all… Sometimes you can get away with a 128x128 lightmap, but you’re better off putting that into a 1024 with 20 other objects so the end result is far fewer calls.
… All covered in the iphone docs 
The main thing is to always think a few times (and expect a few revists) to figure out which is going to be faster, a complete bake, a lightmap bake, how you can cram as many objects onto the same texture as possible, etc
Oh, and remember to also remove any destroyed polys from the UV aswell, no point wasting valuable texture space on invisible/deleted polys.
Yes, when I attach the Object it’s ok, but for iphone performance I must keep all object detached. (idem Startrooper)
But Thank for your answer.
(sorry I m French and my english is bad )
Attach them purely to simplify the uv unwrapping. Once the UV channels are all set, just detatch them again. They can still use the same map.
Ok, thank a lot 
Write a max script to automate the merging and splitting, it will save you a tonne of time, especially if you’re talking about lightmapping scenes that may consist of 40 objects and you want to maintain pivots, links, names, material ID ordering, modifier stacks…etc!