Day and Night System

Can someone here show or explain to me on how I would make a day and night system like in Grand Theft Auto and other various free roaming games. Like how would I make it to where the windows on a building would light up in the afternoon and turn off in the morning. Make a timer that converts Minutes to Hours and Seconds to Minutes.

to do this you will need a lot of programming/scripting as there is no built in feature in blender to do this and i believe it has not ever been done in blender. i am not saying it can’t be done but this would require a lot of work. pretty much, if you have no clue on how you would approach this then you are way over your head. the system that Grand Theft Auto uses took years of research and developing, a huge team of experienced and skilled programmers, and lots of money. basically the answer is no. no one here can show you how to do this as it would take pages and pages of text to even try to explain how to do this. if you want to learn how to do this i suggest taking some 3d programming classes. i dont mean to bring your hopes down, i am just giving you a realistic answer. you can do it but it requires a lot of know how and experience.

A few people have created such systems.

Here is probably one of the best, made by martinsh:
http://blenderartists.org/forum/showthread.php?t=170903

I’ve checked that out already and rechecked about Littleneo’s sun engine and it turns out I can turn the time on it differently. Now I need to know a way I can make windows on buildings light up in the afternoon. Like would this have to be done through an animation technique, add lamp on top of each window to turn it on at a certain time, put on top a luminated texture for each window, or what?

The best way to do that is probably to have a duplicate mesh of the building (with the windows being shadeless and lit up), invisible, and making it visible when the other building mesh turns invisible, thereby switching them out (I suppose you could also use the Replace Mesh actuator); this would happen at the turn of the night / day.

However, the Replace Mesh method may be bad for your CPU to switch all the building meshes at the same time (I’m not sure, I’m just saying it might). So, the invisible / visible method would probably work better, as all meshes would be loaded in when they need to switch at the turn of the day.

 Regards, J

So pretty much adding a plane on top of everyone of the windows with shadeless on ?

Yeah, pretty much, with the plane only turning on when you want it to, and being the same texture as the windows. EDIT: Or, a whole other building mesh, with the windows having emit maps (making them bright, but still on the same texture as the building). This way, the windows could light up the outside of the building (kind of).

Well thanks for the help Joeman!