Slow play when there are large areas

[Internet Explorer]

Hello / Good evening,
I created very large areas in one of my levels. Indeed, forests are giant.
There are bugs that slow the game that became embarrassing. Each time the player turns toward the forest in the level, the game slows down. It does not slow when rotated in the opposite direction, because there is nothing. (No large spaces forests style.)


How can I remove this slowdown? Warning, I do not want to delete the space in my forest. It must keep its large dimensions without slowing down the game.

 

[LavaWave]

It's lag, if there are too many things/objects at once they will eat your framerate, the only solution I have seen so far is to delete some things or hide them behind walls or so, someone might come up with a better solution tough.

 

[Internet Explorer]

By LavaWave : ...or hide them behind walls.

I'll try this.
It'll be a real shame that the level of the contest loses points because of the amount of stuff.

---------- Post added at 08:09 PM ---------- Previous post was at 07:40 PM ----------

It works great ! Thaaaaaanks !