Terrain Grass Deco Layer

[perlyman]

I have searched and searched, but can't find a tutorial on terrain deco layer grass.

What I have learned from the forums:

Grass can be a terrain texture material.
(I would like 3d grass if possible)

or

Grass can be made using a foilage volume
(this requires a simple mesh with a grass texture?)

or

Grass can be made using a deco layer
(this requires a simple mesh with a grass texture?)

looking at some screen shots of the great looking grass I have seen
http://img.photobucket.com/albums/v2...p/UDK3WIP4.png

was that made with the deco layer style or foilage volume?

Any tips or help appreciated

[ThePriest909]

You shouldn't use deco layers for grass for obvious performance reasons. (Decos are meant to switch into a lod actor something you don't need with grass).

Create a new terrain material if you haven't already (manually by double clicking the terrain actor!) and check the option for foliage layers. You just need a simple grass mesh for it.
Once you're done you can also add a wind source somewhere in your scene and animate wind effects just like you wouldbe able to do with "speed-grass".

[perlyman]

Thanks for the reply.

I'm gonna start working on it tonight. I'm making the mesh in 3dsmax, should I model a low poly grass blade, or a small patch of low poly grass?

[ThePriest909]

Just in case you find it useful, I posted a couple of sample-shots below.

I applied a wood material on the basic mesh I made in order to be better visible.
It's just a simple example. Most people just use 2 simple planes crossing each other. In my opinion thought it doesn't look very realistic and especially from the top view, this is why I made something more complex but at the same time I keep the polycount as low as possible. Grass is always a game frame-rate killer.


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This is an example of a grass material. The alpha channel has been used as a mask.



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And last, this is an in game shot of grass created the same way. Note that it's still a WIP and requires some more tweaking but, I'd say that it's representative.



I hope this helps.

[Piranhi]

Where do you get your grass textures from ThePriest, Google always lets me down or I'm typing the wrong phrases into the search box.

[InhexSTER]

Can you please post your grass mesh? I am not so good at max, I would really appreciate that. Or at least screens from left/front and top views so i can try to repeat it

[pipesfranco]

yeah can we have the grass mesh?

[ThePriest909]

I uploaded the grass mesh here: http://www.filefront.com/16044331/grass_01.ASE
It's in ASE format.

@Piranhi, I found links to grass textures from a post somewhere around the UDK forums. I can't find the original post but I kept a link: http://www.loopix-project.com/
There are a couple of free textures there including the one from my example.
The in game shot thought shows a custom made texture. It may sound funny but... I used a hi-Q scanner to scan real grass plants that I used as a base to make the texture in photoshop lol. In my opinion it looks much more realistic than the usual "painted" textures.

[InhexSTER]

@ThePriest909 thank you very much

[iniside]

Well I tried this method and it works well, but I have run in very, very strnage problem.
When I look in one direction grass look normal. When I start look in opposite direction grass getting darker, and darker, nearly black at the end.

Material setup is pretty simple. Single texture with OpacityMask, TwoSided and Mask.

[ThePriest909]

Well I tried this method and it works well, but I have run in very, very strnage problem.
When I look in one direction grass look normal. When I start look in opposite direction grass getting darker, and darker, nearly black at the end.

Material setup is pretty simple. Single texture with OpacityMask, TwoSided and Mask.

Have you tried building the lighting? And if yes maybe try to turn shadows off for that specific actor.
It looks the same way here when the lighting is not built.

[InhexSTER]

@inside maybe try one sided? for me it works, i didnt calculate lighting yet, but seems ok

[pipesfranco]

cheers priest for the texture

[InhexSTER]

Actually after building light have same problem with back of the grass, it almost black

[Piranhi]

haha great idea ThePriest, and thanks for the link

[iniside]

Have you tried building the lighting? And if yes maybe try to turn shadows off for that specific actor.
It looks the same way here when the lighting is not built.

How to turn off shadows for Foliage Layer ? Due I can only disable shadows for terrain but this is not a way I want to do it (nor it work anyway for that matter).

When I place this mesh in level normally it works fine, just when I put it on foliage it starts to behave strange.

[ThePriest909]

@inside maybe try one sided? for me it works, i didnt calculate lighting yet, but seems ok

As one sided you won't be able to see the back side of those planes at all. Not recommended. "Two Sided" and "Two sided seperate pass" should be checked.

[Piranhi]

I also found this package if anyone wants it. http://www.obsidiandawn.com/grass-transparent-pngs

[ThePriest909]

I also found this package if anyone wants it. http://www.obsidiandawn.com/grass-transparent-pngs

Thanks Piranhi, and btw thanks for the feedback on my previous grass material (WIP thread). I 'm so used to the looks of that map that I barely can see the difference between the "forest and the trees".

How to turn off shadows for Foliage Layer ? Due I can only disable shadows for terrain but this is not a way I want to do it (nor it work anyway for that matter).

When I place this mesh in level normally it works fine, just when I put it on foliage it starts to behave strange.

My bad, I forgot that there's no option for editing lighting channels for foliage layers but only for decos. I suppose foliage is set as self shadowed only.
Any difference with anisotropic ligting model material?

[InhexSTER]

What about FoliageFactory volumes? does they work ok?

[iniside]

My bad, I forgot that there's no option for editing lighting channels for foliage layers but only for decos. I suppose foliage is set as self shadowed only.
Any difference with anisotropic ligting model material?

Yes. Texture look like a paint mess. But old problem remains.

EDIT:

FoliageFactory have exatly same problem.

[perlyman]

thanks Piranhi and Priest for the help and downloads!

[iniside]

Ok I found solution for it. In material settings you have to use lighting type NonDirectional. Well, it might look quite brith then, but dont have strange shadows anymore.

[InhexSTER]

@inside NonDirectional property kind of works, but it makes grass very bright and unrealistic, hope to find another solution for that

[ThePriest909]

Guys... have you really tried building the lighting properly, with lightmass on and a proper enviromental color that is not pit black?
If the lighting is not built, it's quite expected to be black from the back side since there's no enviromental light to support it. I'd be surprised if you have problems after the lighting is built.

[InhexSTER]

I have dominant directional light + skylight, everything looks well except grass. Its not completely black from other side its just much darker


and here is backwards (facing light)

[InhexSTER]

actually it looks like it can be fixed by adjusting brightness of both dominant directional light + skylight, i it lowered brightness of Directional Light by 2 and increased by Skylight's by 2

@iniside try using skylight looks like it fixed everything for me. without it back of my trees were also black.


facing away from directional light:



facing light:



I know it does look well yet, but i still need to play with light brightnesss, might need to increase skylight a bit more to make it seem there is more bounced light

[ThePriest909]

Note that the mesh I attached has no secondary UVs. Have you tried generating it?
Not sure if that will make any difference for foliage actors but... Just in case.

Unfortunately I'm at work and I can't test it myself.

[iniside]

Ok. Changing Enc Color to White (with Alpha channel also to 255), solved problem ;o.
Thanks.

[Demrok]

Not sure how old this thread is, but I've run into some problems trying to get my grass to work.

Using a combination of tutorials out there (I plan to write one good one that encompasses everything I have learned) I've used Maya 2010 and ActorX to output my grass mesh and then in Photoshop CS3 I created the texture for it.

But I can't seem to get my alpha channels right =/
the Grass I have now has a white outline around all the blades of grass...


My brain hurts from trying to figure this out.. anyone have any advice?
How should I make my PSD file in Photoshop?
Thanks in advance

[hyawatha15]

Your grass texture probably has a white background. Change it to the color closest to the edge of the grass texture.

[Xendance]

That, or shrink the opacity mask by few pixels. Both work.

[BloodReyvyn]

I kind-of solved (well, faked it) the lighting issues on my grass material by multiplying the diffuse by a constant and running that into the Emissive channel of the Material.

You have to basically mess with the Constants (and possibly multiply your diffuse by a Constant3Vector as well) until your grass has no parts that are either too dark or too bright against the terrain to best make use of the grass blending into the distance.

I recommend adding grass to a designated Grass TerrainMaterial (In the Terrain Material's properties, you will see an Option that says "FoliageMeshes." You can add your grass to this material instead of using that extra texture sample on a seperate Foliage or DecoLayer mask... though if you still want to use a Foliage Layer in Tandem with this technique, you could get some pretty cool results.), but that's just my preference.

Here's a snippet from the material editor (not that it's difficult, but sometimes it's faster to just see an example):



And here is the result:



As you can see no harsh shadowing, whereas, if I removed the emissive channel, I would get much harsher shading, especially if my meshes were shading themselves somehow (as I am only using very low-poly grass it would be much less apparent with this model).

On the previous mesh, where all the lighting seems to be facing one way, you could offset this a few ways.

One of which is making sure you have an ambient light (SkyLight) set up on a very dim setting (0.125 brightness works well) and typically, your light color should be a cross between the dominant color of your skydome and the dominant color within the map itself.

Alternatively (or additionally, as I have used both these techniques in a map before), you could create a Directional Light that is the (dominant) color of your sky and set it to face an opposing direction from your dominant light source (sun, moon, etc) to simulate light bouncing back from the sky itself and this will help light those back faces a bit.

I'd say just mess around with each of these and find a technique and style you like. Running through all of this only took me about 20 minutes, so it's not time consuming at all to give each one a whirl.

EDIT: To that last guy with the white border, there's a property you can adjust here:



That MIGHT help, but even if it doesn't the above posters' ideas should also work just fine.

[Mordt]

Guys, just read through this post and you've all helped me with a similar issue. Thanks again. Great community this one!

[maximsubbota]

hey, the link of the grass mesh doesnt work, it says the file isnt avaible.
Please upload it again, i need this grass mesh.
Thank you