Renzatic on 1/11/2009 at 20:27
ITT we discuss textures and how to make them. I've decided to start a simpler texture so as to cover the basics without getting too complicated. So, without further ado, Part 1...
The base texture. A plaster wall.
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http://users.chartertn.net/greymatt/tutorial/plaster_d.jpgInline Image:
http://users.chartertn.net/greymatt/tutorial/plaster_ex.jpgOne of the first things I do when making a texture, specially plaster, is how the surface should look without the diffuse. Think about how bumpy you want it to be, what the surface usually looks like normally. New plaster is usually fairly flat, only sporting some slight dents and bumps here and there. Older plaster tends to flake off and become more uneven. Since I want to make some old plaster in an old house, I want the surface to be rougher and bumpier.
Starting off, I either make or find a texture with only slight color differences. Something with a little noise, but not so much it drowns out detail and looks sloppy. For the example above, I took a slightly dirty white grunge texture, tiled it 2x2, balanced out the blacks, whites, and greys, tweaked to taste, and ended up with this...
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http://users.chartertn.net/greymatt/tutorial/plaster_bump_1.jpgInline Image:
http://users.chartertn.net/greymatt/tutorial/plaster_bump_ex.jpgInline Image:
http://users.chartertn.net/greymatt/tutorial/plaster_bump_ex_2.jpg...which would be a good base for any old flat plaster texture you have lying around. Bumpy, uneven, with nothing but vague shapes. It could be used as a noise normal on a wide variety of textures.
From here, I'll want to draw out some of the details from my diffuse, but not so much it overwhelms my base. I don't want every black spot to be a dent, or every white spot to be a bump. A stain, for instance, shouldn't draw out any surface features, just lay over it. Here, I'll take the diffuse and do basically the same thing I did to my base bump. Tweak to taste, balance my B&W, run it through the normalmapper, ect and eventually come up with this
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http://users.chartertn.net/greymatt/tutorial/plaster_n2.jpgI'll mix this in with my original just enough to add some extra flavor. The results won't be drastically different, just noticeable enough so it brings out some of the cracks and dents from the diffuse.
From here it gets kind of fun. I have a big selection of random noise normals I use to mix and match to get some rough details out and add spice to the mix. Like I've got a few that's just random dotty noise, one that's just cracks, one that's just bumps. The list goes on. If I want to make something look a little rougher, I'll start stacking these on and see how it comes out.
By stacking on a couple of my details normals, I can go from the above, to this...
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http://users.chartertn.net/greymatt/tutorial/whoa_wall.jpgCRAZY! Just try to keep it tasteful, and use as vague a shape as you can for your detail normals if you go this route. You get too many weird obvious details in there that don't match up your diffuse, and you'll end up with texture float.
So there you have it. A pretty basic tutorial on my method of normal mapping flat textures. Part 2 will be a bit more indepth, with me making models and slapping them in on the above texture to get some neat touches in.
Renzatic on 1/11/2009 at 22:32
Now we get to the really fun part, the modeling. As far as the actual modeling itself goes, that's obviously a little beyond the scope of my tutorial here to teach. So what we're gonna do is focus on the exporting and texturizing of your 3D model to 2D normalmap. From making a nice diffuse, to combining it with another normal to make an entirely new texture. Neat stuff. Woo.
Okay, here's our model. I did this one for the sake of our tutorial.
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http://users.chartertn.net/greymatt/tutorial2/cross_model.jpgNothing too terribly fancy here, but neat enough. It sports enough curves and whoozits and whatnots to make for an interesting normalmap. It's always a good idea to color your model according to what you want it's future material to be, so you can select individual parts easily from a flat colored diffuse coefficient export with your magic wand inside of Photoshop (or GIMP equivalent). Like I want the body of my cross to made out of stone/concrete, and the flat blue base to be made out of...er...maybe painted concrete. Now I could just throw a big texture on there and go through all the effort of tracing the contours, or I can just select whole parts with my magic wand based off the color and slap in a different texture with minimal effort.
But before we get to that, we need to export all our parts. The heightmap, the diffuse, the ambient occulsion, and the normal map. These are the individual parts of the texture I exported from the model above.
Diffuse Coefficient
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http://users.chartertn.net/greymatt/tutorial2/cross_c.jpgAmbient Occlusion
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http://users.chartertn.net/greymatt/tutorial2/cross_ao.jpgHeightmap
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http://users.chartertn.net/greymatt/tutorial2/cross_h.jpgNormalmap
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http://users.chartertn.net/greymatt/tutorial2/cross_n.jpgAnd there you go. Your proto-texture. Don't skimp on the export sizes, either. Make 'em at least 1024x. I've been doing most of my textures 2048x here recently. Remember, if you need a smaller texture, you can always downsize without losing much quality, and it's always good to have a large source handy.
The first thing you're gonna do here is fire up your diffuse in PS/GIMP, then layer your AO on top of that and select multiply. There you go. Your basic diffuse right there.
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http://users.chartertn.net/greymatt/tutorial2/cross_aoc.jpgFrom here, you can be as meticulous or quick as you want to be. Want to just rush through this? Take a single texture, overlay it over your color but underneath your AO, and start cutting til you have things looking the way you want. Your AO will help with your shadows and automatically make things look rounded off. Course the better you want your texture, the more time you should spend with it. But you don't always have to spend 3 hours doing everything. Once you spend some time cutting, pasting, dragging, dropping, blending, ect. You'll eventually come up with something that looks like this
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http://users.chartertn.net/greymatt/tutorial2/cross_d.jpgMy very hasty example here. I just used one texture for the vast majority, one little grunge texture to overlay onsome color, and just slightly offset the main texture for the flat base. It took me about 3 minutes max to do this, but, like I said, you can take as much time as you want here. Once you're happy there, it's time to move on to your normalmap.
This part I've pretty much already covered in the tutorial above. The only difference is you've got a ready made normalmap to import into PS/GIMP or Crazybrush. You've got your exported normal as your base already, so take your new texture you've made WITHOUT THE AO, do your bumpmap tweakery, throw on some noise normals to taste, and after a bit of poking and prodding, you'll have your final texture.
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http://users.chartertn.net/greymatt/tutorial2/cross_dn.jpgNext up, getting it on your wall. This last step is amazingly easy. Really, all your doing is taking your new detail diffuse, positioning and resizing it on the wall diffuse, and doing the exact same thing for the normal. Just cut out the pieces you don't want and make sure all your parts align. This I usually do by positioning and resizing the diffuse and normal at the exact same time on separate layers, and hide the wall normalmap over the wall diffuse so I can just turn one on or off depending on what I'm wanting to save.
Oh, and as for combinging the normals, you don't want to do an overlay or anything like that. Just lay over the piece solid so it hides the details behind it. As long as you don't have any details it can clash against and weird things up, you're about golden. At worst, you might have to normalize. Your end result will look something like
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http://users.chartertn.net/greymatt/tutorial2/cross_wall.jpgInline Image:
http://users.chartertn.net/greymatt/tutorial2/cross_wall_dn.jpg..er. I lost my AO around the outer edge somewhere. Oh well. Also, you can add details and do some blending around the outer edge to make things look a little careworn and homogenous if you want.
And that's about it. If you've got any questions, or you've got corrections and better pieces of advice, feel free to post it all up.
Judith on 31/1/2010 at 21:04
As I was working with snow a bit lately, I thought it might be useful to post a quick tutorial on this. It's not the most accurate method, but it's pretty fast.
IntroductionIn this tutorial you’ll see how to make snow on your textures using your diffuse.
Colors - general approachBefore we start, it’s very important that you know the proper approach to color ranges in your textures. This is important not only when comes to snow, but in general, and in all games, regardless the engine.
First thing you have to remember is to avoid pitch black and pure white on your textures. Remember that the diffuse is just a base for the game engine to work on. Your normalmap will probably add some dark edges when the light is cast on the surface, and the light itself will brighten the texture. Your speculars will enhance the reflection effect. If you have pure white sections in your texture, this color will bleed onto nearby areas. Also, if your engine uses post process effects like bloom or HDR, your texture will be one big glowing ball of light. You’d certainly want to avoid that.
Other colors are important as well. It's best to make them desaturated a bit, so you leave some place for interaction with lights, ambient brightness, post process effects and such.
While you’ll have to roughly evaluate the desaturation by just looking at the texture you made, the black and white colors can be „trimmed” using specific values in your Levels tool. It’s best to use one range per whole set of textures to ensure they react to light in the same manner.
To avoid pitch-black colors I use the value of 8 and I’m setting the maximum white value to 224.
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http://t3edleveldesign.files.wordpress.com/2010/01/02_snow_tex01.jpg?w=640&h=480Preparing a snow layer from diffuseDuplicate your diffuse layer, put in on top and desaturate it. Use Levels and click the Auto button to get maximum white/black range. Now play with the sliders in Value channel to get the desired amount of snow. Usually the range between white and black would be pretty small.
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http://t3edleveldesign.files.wordpress.com/2010/01/02_snow_tex02.jpg?w=640&h=480Sometimes you may want to perform other operations on your texture before using Levels, e.g. when you have dark bricks with white mortar, you’ll get snow only in the brickwork - you have to Invert the image.
Now go to Layer menu, choose Color to alpha and pick the pure black color. This snow is far from perfect right now; you have to tweak it a little. First of all, it's pixelated. Use Gaussian blur to make it smooth, but try not to exceed the value of 1. Otherwise it will be too blurry. To make the transition between texture and snow even smoother, you can duplicate this snow layer, blur it with the value of e.g. 3 or 5 and set the layer to Overlay mode. Play with opacity of both layers to get the desired result. You may also need to use other tools to remove the snow from places you don’t want it to be.
When you’re finished, merge the layers and use Levels tool to correct the black/white color range. First, use the Auto button to calculate the optimal color ranges (you may need to adjust them manually), then use proper values (e.g. 8 and 224) to set the range for white and black.
