problem with the speed of the game ???

Hi... I created a map for my game on 3dsmax, then exported to unity3d as FBX file .

then I add 4 Directional Lights , and put them from the 4 directions .

the problem : When I run the game with the 4 lights the speed become very slow . but when delete 3 of the Directional Light and run the game , the speed will be so nice .

so what I have to do ? specially my Map is big and I have to put 4 lights


Directional lights should be used sparsely. They are global illuminators in which all the world objects are faced with light from that direction. Have you tried using point lights in areas in which you want more lighting and a single directional light to represent a sun (or dominant light source)

In addition to Bryan: Try settings your camera to Deferred lighting. This technique can do way more lights than the default `forward rendering`. You can change this setting in your camera. Or you can change it in the user settings.

Click Camera Gameobject -> Camera Component -> Rendering Path -> Deferred lighting.

If the map is the only thing in your game, you should reconsider your design, because that seems like you are using too much vertices which cannot be culled (clipped away).

Unity uses a method called Frustum Culling, which clips every object out of the draw loop if it is not inside the camera view. If you are creating just one gigantic object, Unity cannot clip it. If you define multiple loose objects in your map, unity is more likely to clip your objects when they are not visible.

There are more and more optimizing techniques which I cannot describe all here, but it also relies on your model and not only on your light sources.

Also: Using 4 directional lights that are all opposite to each other is more or less.. useless. @Bryan states a giant pointlight. Very nice. Or maybe just crank up your Ambient Factor. Ambient is a bit of light that is everywhere in your scene. The ambient factor stands for: the light that gets reflected by all objects. So, its ambience in the total scene. Mostly, even by night, there is some ambience. A little grey or blue does the trick.

For rendering an object, it works like this: `For each pixel on the screen -> check all lights`. So, an increment of 3 extra lights is indeed very heavy.

If you have any more questions, just comment under this post, so I get a notification.

thank you very mush for your answers