Vegetation in HDRP

Unity Engine
1

Hi guys, I will post this concern that I have about doing vegetation in HDRP.

First let me explian the four images:

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Image 1,2,3, I’m using Lit HDRP Material with Material Type in Traslucent, I created a diffuse profile.

I detect some issue in the specular component that I can’t get rid of. It’s like a “wash out” in the color.

Take in mind that for testing purpose, I set smoothing = 0, that mean full diffuse, because increasing the smoothing > 0, the issue is stronger.

I placed a reflection probe (RP) around only to the bush to have control about the reflection (for testing purpose).

In the Image 1, the intensity of the RP = 0, that is why the issue only appear in the specular of the direct lighting.

In the Image 2, the intensity RP = 1.

In the Image 3, direct lighting in intensity RP = 0.

And if I use Standard material type instead of traslucent, well, is even worst.

I saw Unity example where there are using vegetation, and look so realistic, I don’t see that handle with this problem.

I’m using something wrong, or I’m misunderstand some parameter??.

In unity

Thanks
Eduardo.

NOTE 1: just last question in the shader graph, aren’t we able to use traslucent material yet, right?

NOTE 2: I’m using SpeedTree pack, but the speedtree material are not update yet to HDRP, so I’m creating my won materials.

1 Like
2

I think the clue is somewhere there, in your textures.

You can download the book of the dead demo scene to examine how to prepare materials for HDRP vegetation.

3

Hi thanks Hippocoder.

I dowloaded “The book of the dead”, where in fact I don’t see the problem in the vegetation, I bring this vegetation into my test project, and I don’t see the issue that I mentioned previosly.

Actually the materials are similar.

So, I did this, I assigned in the quixel asset the material that I created for the speedtree bush.

And actually look as I expected.

That make me think that probably is an issue in the SpeedTree asset?, I don’t know perhaps, I realize that meanwhile quixel asset are .fbx, speedTree has its own format.

Probably need to wait until SpeedTree update its packages to work with HDRP.

4

Hey, I was struggling with the same ugly specularity with my own self-made vegetation assets and I realized that the effect was strongly emphasised by the custom edited normals which I had made. It’s a common technique to edit the normals for a more round and even look, but it really seems Unity’s way of handling them results in odd specular reflections. Exporting my vegetation model with the default flat, planar, uneven-looking normals looks better in Unity.

5

Sorry for the bump, but almost two years later and this is still happening. Why?

In normal conditions, edited vertex normals look much better for foliage, but that damn specularity ruins it all. The effect is very visible when seeing the asset backlit. Any ideas? Unity devs, please?

6

I’m having the same issue with trees made in Speedtree and exported as FBX.

7

Is there any solution for this? Having the same issue ruining all scene :frowning:

8

Actually, I found the solution using Speedtree 8, when I posted the question I was using ST 7. Actually v8 fix the problem.

9

Yes but what about custom trees? im not using speedtree for doing them.

10

Anyway, trees and grass need to be heavily modified according to their needs.