Lightmap Issues

[diabi85]

Hi guys!
I'm trying to create buildings by using the modular creation approach, but I'm having big problems with lights!
All my meshes have custom lightmaps created in 3ds max.
Windows lightmap resolution is set to 256 while is 32 for the other meshes.
There are no overlapping faces in the UVs and everything should work fine.

RED: It seems that shadows cast on one mesh are repeated on other instances of the same mesh!How can it be?
BLUE: I don't understand what is that weird shadow on the side!
GREEN: the sign doesn't cast any shadow on the ledge or on the wall on the left!

Only Lighting


RED: It seems that shadows cast on one mesh are repeated on other instances of the same mesh!How can it be?
BLUE: I don't understand what is that weird shadow on the side!
GREEN: the sign doesn't cast any shadow on the ledge or on the wall on the left!

Lit


Heeeelp!!!I,m really going mad!

[diabi85]

UPDATE

Now I officially don't understand the lightmap system.
I tried to work on the ledge with the shadowing problems: re-unwrapped the 2nd channel, more padding, more attention to smoothing groups,etc.
Then in Udk I tried to tweak the resolution from 32 to 512.
Results are quite weird...

32

the ledge looks ok. the shadow on the right is not repeated on any of the other instances of the mesh.Only partial shadows from the sign (maybe because of the low resolution?)

64
The shadow on the right is not repeated.
Now there is a weird shadow on the left, but just on two meshes...the others on the left are fine.
The short ledge has now the weird shadow on the side as seen in the first post.
The shadow cast by the sign looks better now.


128
All the shadows look fine again.
So far the shadow from the sign looks ok.


256
Shadow on the right side of the ledge repeated like in the first post.
The left side looks ok.
Now the sign doesn't cast any shadow on the ledge (except for a very little spot) instead it is perfectly cast on the window....unfortunately is repeated over all the windows meshes...
Probably the weirdest situation.


512
The ledge looks fine, but it doesn't receive any shadow on the right side from the column.
The sign doesn't cast any shadows except for a little spot.


Can someone explain me what is going on???

[daniwrig]

That looks like a bug for sure. Try setting bCombineSimilarMappings to False in your BaseEngine.ini.

[diabi85]

Cool! IT WORKS! Thanks!!!

Does it affect somehow performances?

[daniwrig]

Disabling that will cause a little bit more lightmap memory to get used. We really need to disable it though because it's not very robust as you can see =(