How to add (realistic) wind motion to tree meshes?

[Ravneson]

Hey all,
I’ve been trying to get a grasp on how to go about adding speedtree-like wind-motion to a bunch of tree mesh assets I bought (not enough time to replace them with speedtrees, unfortunately). Sadly I haven’t quite been able to figure out where one starts with that, I’ve come across a few tutorials aimed at making grass/small vegetation move via blueprint, but I don’t feel that is very satisfactory for a tree that does far more than “ripple” back and forwards. Anyone know where I should start/what tutorials out there are relevant ?(I keep coming across UDK tuts, but not sure if they still work (?) and want to get it right from the start…)

Thanks!

[FrankieV]

Just add a Wind Direction Force and your tress should start moving if they are already set up

[anonymous_user_923c79df]

Do you want to create something like a swaying trunk + leaf wind effect?
-either use the speedtree wind ( suggestion)
-or use the wind nodes in the material editor (flipbook or simple grass wind): -> you will have to play around a little bit with the values to get a good result
-for a “swaying” effect -> take a look at my free vegetation pack

[Mugluck]

Also don’t forget that you can paint weights onto the tree meshes and use those to control wind forces on different parts of the tree. It’s basically a greyscale map for the vertex information on the tree. You plug it into the weight on the simple grass wind and control for individual branches and stuff.

Also don’t forget that a wind directional source can be found in the placeable classes if you search for it. It’s not dynamic at the moment, so you can’t change it at runtime, but it works fine once you’ve placed it.

[Ravneson]

@;279694

Do you want to create something like a swaying trunk + leaf wind effect?
-either use the speedtree wind ( suggestion)
-or use the wind nodes in the material editor (flipbook or simple grass wind): -> you will have to play around a little bit with the values to get a good result
-for a “swaying” effect -> take a look at my free vegetation pack

Thanks but I already have a bunch tree assets (mega nature pack…) that I’d like to have animated so the behave like speedtrees in the wind. I’ll look at the wind nodes, see if that does it.

@Mugluck;279719

Also don’t forget that you can paint weights onto the tree meshes and use those to control wind forces on different parts of the tree. It’s basically a greyscale map for the vertex information on the tree. You plug it into the weight on the simple grass wind and control for individual branches and stuff.

Also don’t forget that a wind directional source can be found in the placeable classes if you search for it. It’s not dynamic at the moment, so you can’t change it at runtime, but it works fine once you’ve placed it.

That sounds like what I’m wanting to do, but I have no clue as to how to go about it? Do I use something like the textures for branches as a base, paint a greyscale map in photoshop & add them in UE somehow? (sorry if that’s a silly question, very new to this whole part of UE)

[Mugluck]

I’m guessing you have a UV map of the trees? Try painting that in greyscale. You should be able to import it like most textures. It really depends on how the UV’s of the trees were done as to how easy it will be to do. But in theory you should just be able to paint over the branches and save that as a heightmap.

[Ravneson]

Hm, is there a way to extract a UV map from a UE asset? (I only seem to manage to get a .fbx out, but unsure how to proceed from there)

[Ravneson]

Ok, have had some luck with vertex painting, but it seems like all I can do is add the SimpleGrassWind to a Lerp node which gives me a swaying motion, but that doesn’t look entirely convincing in terms of motion. Is there anyway of binding the movement to the wind direction, speed & gusting? (Or should I reconsider replacing everything with speedtrees?)

[Mugluck]

This thread might help a little:

https://forums.unrealengine/showthread.php?2613-SimpleGrassWind

But essentially controlling wind is pretty finicky and wierd, but you can use maths to do it. Start getting to know sine curves, and panners and so on. Use cloud textures and the like. They can work with different masks. If you’re not using speedtree, it’s all in the math.

[FrankieV]

@Ravneson;280065

Ok, have had some luck with vertex painting, but it seems like all I can do is add the SimpleGrassWind to a Lerp node which gives me a swaying motion, but that doesn’t look entirely convincing in terms of motion. Is there anyway of binding the movement to the wind direction, speed & gusting? (Or should I reconsider replacing everything with speedtrees?)

Well a tree made for Unreal 4 is rather useless if it already does not have the ability to react to wind forces free or not. There are already a few free foliage packages under community content that included an assortment of trees and more than enough to make up an entire forest (some even of equal or even better quality than a speedtree) which reacts to wind.

[jonimake]

GPU Gems 3 shows how Crytek did it in Crysis 1. It’s a pretty simple thing to implement in UE 4: https://developer.nvidia/gpugems/GPUGems3/gpugems3_ch16.html

[Ravneson]

@;280614

Well a tree made for Unreal 4 is rather useless if it already does not have the ability to react to wind forces free or not. There are already a few free foliage packages under community content that included an assortment of trees and more than enough to make up an entire forest (some even of equal or even better quality than a speedtree) which reacts to wind.

I agree, sadly that mega nature pack I’m attempting to use is woefully lacking in regards to wind (but has the perfect art style for what I’m working on, unlike speedtree which don’t offer the right types of tree).