How to paint trees on imported geometry

Unity Engine
1

Hi,

We are working on a mmo game and would like to know if its possible to paint using the Unity brushes, trees and grass on imported geometry?

If not is there a way to get the “billboard” effect that comes with Unity tree system on imported custom trees (that would just be duplicated by hand) that we duplicate into our scenes?

Our basic problem is we we need to have terrain that has undercuts and caves etc… but need to performance of the tree and vegetation system that is possible with the Unity terrain. Currently when I copy paste to duplicated imported trees my performance slows down after just 10 or so trees placed. Using the same tree in the Unity terrain system as a brushed on object the performance is far better even with 50+ trees in the scene.

Does anyone have any ideas?

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2

Terrain painting you can’t do really. For trees and grass, they really only work on the terrain but, depending on your geometry, you may be able to get the terrain to closely match the imported models (get it right below the level of the model) and paint the trees onto that. They’ll be slightly inset into the ground depending on how close you can get the terrain to the model surface.

You could try multiple terrains for this, but it might have an adverse performance impact. You could also look at using the UnityLOD system to keep draw calls and poly count down w/o using Unity’s tree system.

That’s what I’d try, but someone will probably come up w/ a better idea if that doesn’t work out.

3

Fast forward to 2018+ and you can use polybrush
https://docs.unity3d.com/Packages/com.unity.polybrush@1.0/manual/index.html