Hey there,
whenever I apply a texture with transparency on custom meshes, the meshes become invisible. I’ll demonstrate it with two pictures:
A square from UE4 with the material
My tree with the material
The material has no transparency
The square from UE4 applies the material as it should
My leaves are invisible
The material has transparency
What did I wrong? How can I fix it?
Looking forward answers!
Did you UV unwrap the planes you’re using for the tree, to fit the texture?
Is your texture ‘2 sided’ ? 
Good call. If you look closely on the square, it doesn’t actually look like it is. 
Hey there, thanks for your answers!
The planes aren’t actually planes but really thin squares. Even one-sided, I should at least see the texture from one side. Every self made model (convertet to .fbx by blender) has the problem. Downloaded meshes work fine. I actually don’t know what you mean with UV unwrap, I’ll get into it when I’m back from work! Thanks for the idea.
Without UV unwrapping, the image doesn’t have a clue about how it should be placed on your plane (or your box).
If you look at the first image you posted, it’s nothing but this mossy green color. Perhaps you’re only seeing 2 tiny pixels from your actual image. I can’t say this more detailed than the lien above; your image simply doesn’t know where it should be placed on your plane/box, or even how big/small it should be.
Other than that, you should make them two-sided so the leafs will be seen from both sides of the plane/box 
Hope this helps!
Glad that you figured it out mate!
Good luck with your project!
Yes it does look pretty. Not jealous what so ever!
