Quality Foliage

Tetranome

Hey, I'm currently working on a variety of foliage assets - however the tutorial series I have been following is for UDK, whereas I'm working in UE4. It hasn't been a problem until now - creating materials. There isn't a custom lighting input, apparently because of the use of deferred rendering in UE4.

I'm trying to hit the quality of the below image -

Skyrim Mod:



However this is what I have at the moment -

Grass:


Shader Network:


Any ideas for giving my grass a good quality boost to get that specularity? I'm a bit lost as I'm quite new to PBR and how to change UDK workflow to fit UE4.

Thank you! :poly142:

Der Hollander

One of the things to keep in mind with a lot of those Skyrim screens is that third-party post-processing is usually involved via injectors such as ENB.

Things I might try -
- Turn your Roughness down from .8, give it a little more smoothness.
- Put in a proper normal map, right now there's nothing but the geo for the lighting to calculate, so you're only getting whatever is there in the geo instead of interesting layering.
-You might try tossing in like a .05 or something in the metalness or putting in a spec value to boost the highlights that come off the grass. For extra oomph, put in a Two-Sided node and have one side brighter than the other, as the underside of grass blades tend to be rougher than the side with all the photosynthesizing cells.
-Lastly, you're going to want to mess with the post-process settings, mainly colour correction and SSAO, but that should be your last step after you really dig into the materials and get it looking sexy.

Ramseus

Also your vector that you're plugging into the normal input is probably not doing what you think it is. Normal maps are based on a [-1,1] base range, beyond that you'll be overdriving the normals. And values in Unreal are simply decimal (1.0 = #FFFFFF = 255,255,255). Blah blah, your value should be 0,0,1 for a neutral normal colour in unreal. But that's still not going to look like anything. The Skyrim mod grass looks like it has some heavy normals on it for shading, probably baked from high res geometry.

I don't know how you went about creating your grass texture so far, but in my experience modelling high res grass (or making it out of fibers, or a combination) is a lot more effort than painting it in photoshop, but so worthwhile since you're able to get so much more out of the engine's lighting with nice, clean, accurate normal maps.

JedTheKrampus

Are you using the two-sided foliage shader that's in UE 4.7 preview? Because if you aren't, you probably should be.

Tetranome

@Der Hollander
Thanks for the feedback man. I think it's mostly the lack of a normal map, however the geo of my grass blades in maya don't have the hard edge of a grass blade, so I'll have to start from scratch haha. No worries though, if that's what it takes eh! The roughness is so high because there's like a collective circular gleam if it's any lower, but I figure that's because of the lack of surface definition - a normal map! Once I get that puppy in I can boost the smoothness.

@Ramseus
That's great, I didn't know that - as you could probably tell! Thanks for that tip. I'm going to restart and create my geo with some hard edges in the middle (like most grass) as my current geo is pretty rounded. Thank you for the pointers!

@JedTheKrampus
I am, but you had me doubt myself for a second there haha. Thanks for the tip

teaandcigarettes

Hi Tetranome,

If you're following the 3dmotive foliage series, then I'm the voice in the video

I haven't had a chance to dig in into UE4 properly yet, but I've been doing a lot of foliage in CryEngine these past few months, so I can offer you some general tips on how to make your foliage look more next-gen.


1. Make sure you have a normal map for grass and leaves. Ideally you want your high poly meshes to point towards odd directions and to have as much volume as possible. When you look at your highpoly mesh from the side it shouldn't look flat.

2. Play around with spec, fresnel and roughness/gloss. If your normal maps are strong enough, you should be able to get some really nice reflections that will liven up your foliage.

3. Subsurface scattering is extremely important. I don't know the UE specifics, but if it accepts greyscale inputs, then it is good to use a heightmap of your highpoly grass/leaves as a base. Then, make a selection of your alpha mask and mess around with Refine Edge in PS to make the edges of your leaves slightly brighter. On top of that you might want to paint in some subtle tonal shifts or use gradient overlays.

4. Get your grass to cast shadows if possible. It will really help the visuals. Try to make the shadows slightly lighter than the rest of the environment if possible.

Overall I don't think that much has changed. You might want to stick with principles of PBR and avoid having too much of prebaked AO. Prebaked reflections and lighting are probably best removed completely. You should be getting your lighting from normals/spec/gloss.

Joopson

Also, the diffuse (albedo, base color) for the grass in skyrim seems to have a lot more contrast to it, and Ambient occlusion baked in to give it depth and detail. I think that alone would help a lot.

Tetranome

@teaandcigarettes
Haha that's awesome that you saw this. Yeah it's the 3dmotive tutorial. I'm going to go back and remodel the geo and make it more interesting, and i'll be sure to have them take up more volume for added depth. As for subsurface scattering, I believe there's a node for it. I'll mess around with it for sure, and I'll try to get some nice shadows going too.
Thanks for the help!

@Joopson
Yes you're right, along with SS that should really get things looking nice. Thank you!

Thanks for all the tips guys, I'm learning a lot

UPDATE: Things are going well! Still working on it, but hot damn SS and a new normal map made a huge difference.

I do have a question though. My baked shadows are too harsh (not in the below image), how can I change up the strength of the shadows cast specifically by grass meshes?

Assassinaded

Have you tried imputing spec info or emissive?

paradoxical-pixel

@teaandcigarettes Wow! I didn't realise that tutorial was by you! I remember finding it really useful back in the UDK days.

Unless my memory fails me, wasn't the whole purpose of using the Custom Lighting input to overcome a UDK shader bug? Presumably this bug hasn't been dragged through into UE4, making the use of Custom Lighting unnecessary.