i have a problem with the terrains i make.
whenever i place out trees they look really good. that is until i test play. when i test play, and i aproach the trees, they kind of starts to float. when i go backwards the trees get lowered back to normal. how do i fix this?
oh and do you mind explaining how i can make them bend in the wind (like the grass)
The “floating” can be fixed by tweaking the tree billboard distance and fade distance. You should have a look through the docs.
how do i change the billboard distance and fade distance? i couldnt fint it in the link you sent me
nevermind. i figured it out 
Trees still float, you just don’t see them pop into floating position, which maybe hides the problem some. Unless they are standing on a hill, and you suddenly see sky below them 
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Fixing the floating issue is a UT task, by rethinking which rotations to link between the main cam, and the imposter cams, rendering billboard textures. Or by calculating the imposter rotations by trigonemtry instead.
For now the only thing to do, is do some coverup in the shader, by stretching the billboard to the size it should have had.