Sky / Foliage in UDK

[Tom Ellis]

I've posted this in the UDK thread but it seems a little sleepy in there right now and I'm anxious to get moving on this project as I've hit a bit of a roadblock.

I'm pretty new to UDK, and this is the first time I'm attempting a complete 'environment' in it. Previously my experience was pretty much limited to importing meshes and creating basic materials simply for the sake of presentation renders.

My first issue is with creating a sky. I just have no idea how to do it. This is one area that seems to be lacking in the documentation / tutorial vids and even Google doesn't return much help other than dropping in a Skydome.

I'm guessing a Skydome is the most appropriate way to create a sky, but if I wanted to create my own, how would I go about this? IE what kind of mesh / meaterial would I need to create, and also what kind of image would go in the diffuse? I'm guessing some sort of panoramic map but I have no idea.

Secondly, I'm having problems with foliage/ground clutter.

I've got a reasonable looking terrain along with a few terrain materials, but I want to cover it (like really COVER it) with grass, which I intend to do with alpha'd crossed planes, but I have a couple questions about the best way to achieve this.

I've attempted using DecoLayers but this has led to a number of problems. Firstly, I think DecoLayers obviously work on the tesselation of the terrain as they appear to only get placed at vertex points in the terrain mesh. This obviously looks crap since the meshes are being laid out on a 'grid'. Is there another way to scatter grass meshes? I'm sure I read about another method that doesn't calculate collision detection and allows for a better placement of such small meshes.

Is it even possible to literally cover the ground in meshes or will it ultimately need to be kinda sparse?

Thanks!

[DarthNater]

When I wanted a custom sky, I just created a sphere, cut it in half and flipped the normals (so they all point into the center). Unwrap this as flat and straight as you can.

Then I just got a sky texture from CG textures and edited it to my liking (made it darker).

Look at the ones in their currently, and their material set ups.

As far as the decolayers go, I haven't played with them too much so I can't help you there :P

[Tom Ellis]

Thanks man, much appreciated.

So it's just the foliage thing then, really struggling with that!

As a side note, does anyone know a good place to grab some textures suitable for using as foliage (crossed alpha'd planes) Ive got a 3DTotal plants/trees DVD which comes with alpha's/diffuse, but unfortunately there's only like 4 grass images and even with a bit of duplication/variation, they're not looking that good.

[DarthNater]

Oh I also forgot to add (and I think you'll notice this with the UDK skies) I scale my half sphere downward in the Z direction (to squash the mesh). A round sky looks funny :P

As far as you're grass textures go, its a pain in the ass but I always took references of grass from the side and just cut them and created the images myself. I don't really know where to find awesome textures, but I'm sure they are out there....

[Tom Ellis]

I thought you were gonna say that, I've considered manually cutting out some grass/plants but I know it's gonna look bad or take hours!

[Eric Chadwick]

This might help too
http://wiki.polycount.net/CategoryEnvironment#ES2

[Tom Ellis]

Ah nice one Eric thanks, yeah there's definitely a few articles in there that will be of great use.

[Eric Chadwick]

I kinda meant the two sky ones in particular, since they're for UE3.

[Tom Ellis]

Yep the skybox>skydome article will be a great help for sure. There are some others in there which may well come in handy later though!

[JordanW]

this should help with foliage:

http://udn.epicgames.com/Three/ContentBlog.html#Advanced Mesh Placement

As far as skies go, we usually create a dome and have sky textures either planar mapped from above or unwrapped sideways, we also will do shader tricks with uv coords to get smooth gradients if we need them (think of just using the R or G of a UV node output as a color or blend value) We also will use additional meshes for cloud layers or something

[SHEPEIRO]

best place for these things, is outside,

when the weathers good (to your liking) go outside somewhere tall or flat and take some photos with a camera with manual settings so that it doesnt adjust to the differing light levels your pointing at.

veg aswell you can get some blue felt then go out on an overcast day rip some veg off trees bushes whatever place on the flattened sheet and photograph bearing in mind how you are going to build the thing

Skies can also be made using max and baked down, start by usiong a series of gradient maps horizontally and vertical to produce a nice base then create clouds from photos (or dynamic fluid solutions also works), and the other objects (moon sun etc) on planes or pushed geometry. then bake to a sky with decent geometry/uvs. Infact you can bake to a sphere mapped like a semi cubemap(very litrtle distortion or pinching)

[Tom Ellis]

Great, thanks Jordan, Shepeiro.

That's a great idea about taking some photo's with a coloured piece behind it Shepeiro!

Much appreciated.

Thanks

[JordanW]

here's an article I wrote on UDN on taking better photos for textures, at the end I show an example of how to take good foliage photos

http://udn.epicgames.com/Three/TakingBetterPhotosForTextures.html

[Tom Ellis]

Nice one Jordan thanks, definitely a helpful article, not only the foliage bit. I never usually take much ref myself due to an inability to light things adequately so this should be useful.

[Eric Chadwick]

Pretty cool rig Jordan, also cool to see the sequence of the skin specular changing with the angle.