Fern leaf objects rendering over one another in Unreal?

PJPayne · May 2020

Hello,

I am sure there is a simply fix for this, but I am just not sure what it is. I made a basic fern, and the objects seem to be rendering in front of other objects in that same fern when they are supposed to be behind other branches, see video below for example.

The example problem

Any help is greatly appreciated

Eric Chadwick · May 2020

Did you know you can embed YouTube here?

https://www.youtube.com/watch?v=dvLwHwoQN9Y

PJPayne · May 2020

I did not, thank you

Eric Chadwick · May 2020

Alpha blend often causes sorting problems, as explained here
https://docs.unrealengine.com/en-US/Engine/Rendering/Materials/HowTo/Transparency/index.html

Most foliage should be using "alpha test". Called opacity mask in Unreal.
https://docs.unrealengine.com/en-US/Resources/ContentExamples/MaterialNodes/1_8/index.html

If you absolutely need partial transparency, you can force the rendering order within the same mesh, by carefully ordering the vertices. It's messy, but it does work.
http://wiki.polycount.com/wiki/Transparency_map#Sorting_Problems

PJPayne · May 2020

So after some searching, I found changing the blend mode to "Masked" and plugging the alpha into "Opacity Mask" seems to have fixed this.

Is by you saying "opacity mask" meaning what I mentioned above?

Eric Chadwick · May 2020

Yes. I guess you didn't look at the link I posted?

PJPayne · May 2020

Sorry, I did but with how you mentioned "absolutely need[ing] transparency" I got a bit confused, and using a video showing where each of these things are is easier for me to understand (For instance with the blending mode and such). I'm not quite comfortable with the UI yet (otherwise I wouldn't asks such a basic question tbh), and using redundancy helps me process these things.

Fern leaf objects rendering over one another in Unreal?

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