I've made a couple trees/bushes with the Sapling add-on and then distributed them over a landscape with a hair particle system. The original trees have a "swaying in the wind" animation and when they get duplicated through the particle system, although the size and rotation of the trees is randomized, their animation remains fairly homogenous: they all sway in the same directions at the same rate.

Is there a way to randomize this through the particle system, or do I need to make multiple source trees with different animations attached to them?

I still want them to look like they are being affected by the same environment/wind but as it is now it's too synchronized. I've already given the different tree types and bushes different wind speeds and amounts of "gust variation" through the sapling generator options, but this doesn't seem to be effective enough.


2 Answers 2


If you need the forest to look more realistic, you would need more animations! One animation for all the trees is simply not enough.

My suggestions:

  • Add at least 3-4 different animations.

  • Make trees swap their animations randomly (e.g. tree1 runs animation1 then animation3...)

  • Don't randomise the rotation because that would look fake (wind blows generally in one direction)

  • Also be careful with the different wind speed as if you overdo this you might get unrealistic results.

  • You can simulate the wind 'gust' by starting the animations on all trees (seed points) which are at a certain position (say in X) and delay the animations of the other trees based on their Y position.

  • To make this even more effective you can actually simulate the wind by creating a huge box or a sphere(s) and animating them, passing through the forest in a certain way. This would be a non-renderable object which would trigger the wind animations on your trees. This could be even further enhanced if you increase the wind speed based on the proximity of the tree to the sphere centre, for example.

  • Also don't forget that even if you nail the whole wind animation, if you only have one tree model (despite different scale/rotation), it just wont work. You need more variation, only then you can play with randomness.


Animate your tree using shape keys. Remember that the verts move more or less straight to the target so you may have to do some tweaking. Doesn't take a lot of movement unless your wind is very strong. Set the minimum to -1 to get a full range. Once your shape key is made, set a key at mid position. Open your graph editor and with the shape key selected apply noise to it. Adjust the wave length to slow it down and adjust the intensity so it doesn't go beyond -1 or +1. Apply different shape keys for forward/backward and left/right with a different noise modifier for each that will give you a random looking movement. They still will all move the same unless you duplicate the tree and change the paramenters. The more trees you have the less they all appear to move together.


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