Terrain and resource question

Unity Engine
1

Hi all !

For a Flying game that i am working on, i need to generate very large maps/terrain.

I was thinking about making a big square of 9 terrains. 3*3

⌈⌉⌈⌉⌈⌉
⌊⌋⌊⌋⌊⌋
⌈⌉⌈⌉⌈⌉
⌊⌋⌊⌋⌊⌋
⌈⌉⌈⌉⌈⌉
⌊⌋⌊⌋⌊⌋

Each terrain is 8000*8000 size.
Let’s say that i would like to instantiate all those 9 terrains immediately on the scene.

My question is the following : Does the camera culling distance have an impact on performances ?
For example, if i set the camera culling distance to 4000, does Unity calculate the non visible terrains areas ?

Is 33 with 4000 culling dist give about the same performance as 99 with the same culling dist ?

Thank you very much for any feedback.
Best Regards.

2

the culling is less a problem than the memory usage of the terrains.
the far distance will define which terrain blocks and chunks on them are going to be rendered at a time not so much a problem.
but if you don’t keep your heightmaps and detail maps low enough you are gonna pay with massive ram for it if you don’t stream it

3

dreamora, thank you for taking time to answer.

Hum, i see…
So, right now, i am using 33 terrains with a 513513 heightmap on each of them.
Maybe instantiate them all at the same time may not be a very good idea then ?

Terrain solution is still better than using a big mesh right ? (I read that in some other threads.)

Also, i am not sure but, it is still not possible to make any holes on the terrain right ? I have a large part of my terrain that represent the sea (0 elevation), so it is a little bit a wast to render it (i have a plane which is around 5 elevation)…

Again, any advices are very welcome.
How would you have proceed to make a very big terrain with minimum memory cost ?

4

without streaming it can at best only be equal.
REason is that

  1. Terrains are no meshes
  2. Terrains themself consist of several chunks so its not like the whole terrain or nothing is rendered, its decided on smaller blocks from the terrain itself.

And no, the terrains are heightmap based with a continous grid so no holes can be created.

as for large terrain and minimum memory: Unity Pro + asset bundle streaming (P|Terrain as an out of the box solution)

5

It’s not that big of a deal (on a typical computer, not something you’d want to do on a mobile device).

–Eric

6

dreamora, Eric5h5, thank you very much for your input.
Some very useful info there.

Best Regards.