Trees, plants and performances for archi viz, what is the best approach ?

Unity Engine
1

Hi,

I’m currently working on an interactive version of these two towers in Saoudi Arabia: Towers

As you can see there are a lot of trees and plants… My main issue on this project is the performances because we’re doing aswell CGIs and flythrough, the 3D part of the studio is working on a “middle version” halfway between low and high poly so the scene will be heavy and not fully optimized and I don’t have the time/budget to optimize it. My boss wants a lot of trees and plants and to make it beautiful, fantastic and amazing…
So I know that i’m gonna have performances problem for sure, and I’m trying to optimize everything as much as I can in unity (i’m the only 3drt dev :s)

I’m doing few tests about the trees because I know that in all our project theses have always been the most performances “crushers”…

Currently, i’m trying few things: (i’m using the palm trees from the terrain asset editor)

  • insert the trees in the model file (3ds-fbx) and merge them as two or three objects. Once imported the nature shaders (bark and leaves with soft occlusion doesn’t work).

  • if i’m trying to add them in unity tree after tree and group them into 2 or 3 empty gameobjects with the combine children script, well they dissappear if there are too many of them to combine or the shader doesn’t work (like the previous test) if they are not too much…

  • Now I’m going to try to add few terrains under the ground and plant the trees on them (i never tried that), is that a good idea or the fact that i’m using multiple terrains (10-15 of them) with few trees on each will kill the performances

I’m preparing the viewer (Interface, optimization, differents levels for the appartments and facilities to visit) and I’ve got few day to release a demo which looks as best as possible with really low poly models, so i’m adding trees, plants, animated cars, birds,…

If you have any tips or idea to help me with the performances and the trees/plants stuff that would be more than helpfull.

Here are screenshots first is the first test (combine in 3dsmax), second is with the palm trees in unity with the combine children script (obviously it’s a “before alpha version” ^^

721925--26196--$Trees_problem.jpg
721925--26196--$Trees_problem.jpg1280×834 237 KB

721925--26197--$Trees_problem02.jpg
721925--26197--$Trees_problem02.jpg1280×834 340 KB

2

up!

3

I’m trying something else, I’m going to hide a big terrain under the scene, use the set height to have all the different heights where i need trees and plants, place everything, and then optimize the terrain. I’m notice that after sculpting the terrain and set the heightmap resolution to 129 the terrain appears flat and the trees stay at their place, obviously I can’t get back the sculpting after that, but I would like to know it that could have a bad effect later on ?

What I need to do is place trees and plants and I don’t want the ressources to be used by the sculpting of the terrain, is there a way of turning off the rendering of the ground ?

I’m going to run out of time soon on this project… :s

4

up

5

Sorry to bump this again, but at the moment i’m raising the terrain to have the same sort of shape of my base ground of the tower plus the center around the pools… and it’s really annoying. I’m using aswell few terrains for some zone.

  • Isn’t there any better solution to do that?

  • As we never see the terrain itself, is there a way to not render it (only the trees) or not render the height of the terrain?

  • Is there a way to keep the nature occlusion shaders to work after a combine children ?

Thanks a lot for your help.

BooBi