<a contenteditable="false" data-ipshover="" data-ipshover-target="<___base_url___>/index.php?/profile/10211-jesta/&do=hovercard" data-mentionid="10211" href="<___base_url___>/index.php?/profile/10211-jesta/">@jesta</a> I actually don't know how to do this, when Shock mentioned it just went straight over my head and I could not even think about how it can effect shadows and snow at the same time independently.
However, I did just try to make a road texture. When I made it, it would become so snow covered in the winter, that you could not see it. The mod kit did throw up a warning when it was built, saying that the texture I used had an all white alpha channel. So I changed this to a transparent alpha channel, and the roads now show up in the winter. That leads me to think that maybe the snow covering is due to the alpha channel of the AO not the baked AO itself?
I think this might be something worth playing around with. Perhaps, open the AO in gimp. Then copy the AO into another layer, so you have two identical layers. Then, in the bottom later invert the picture, so the black areas (edges... shadows) become white. Set the new black areas (the old white areas) to transparent, and save it. Then it might give you some cool snow effects, if it works the same as a road.
I have not tried it, and I could (probably am) be completely and utterly wrong, but after making the road perhaps this is how it works. It will be cool if it does!
As for the white AO, I used to use it too when I could not get AO to work. However, it does interact with the lighting of the game. Without the AO, I find that in 'rain' the buildings are very bright and in 'sun' they are quite washed out. The AO tempers this, as it interacts with the environment lighting in the game as it changes between seasons. So in 'sun', the AO results in stronger shadows on your model, while in 'rain' it diminishes a bit. It adds more definition to the model, that you will not get with a pure white AO or with an overlaid AO.
