Rock Texture Tutorial

O.k. forget what I said previously about how to create rock textures (its fine for drawing overlays though) I found a much better and faster way to create highly realistic rock textures in photoshop.

First thing to do is to pick a light color and a shadow color for your rock, do this by setting one as the background color and the other as the foreground color. Then do Filter>Render>Clouds. Then do Filter>Noise>Add noise and set the amount to something low like 3%, set the distribution to gaussian, and make sure its monochromatic. What you just created will act as the diffuse texture for the rock.

Now go to your channels tab and create a new channel. Select this new alpha layer, and make sure white and black is your foreground and background colors, and do Filter>Render>Difference Clouds and add noise to it with the same settings as before. This new layer is going to act as a height map for the rock, and the noise you just created is supposed to read as small little bumpy pits in the rocks, however as the noise is right now it might be too harsh, so go to Edit>Fade Add Noise and fade it by about 50%. You now have the choice of keeping your heightmap as is or modifying it, but let me show the final step then I'll get to modifying later. You might want to save your progress at this point.

The final step is to reselect your RGB channel, the go to Filter>Render>Lighting Effects. There are alot of options here but the first thing you want to do is is set the Texture Channel (at the bottom of the pop up window) to your heightmap (probably called by default alpha 1). The preview window will now show what your final texture will look like. Here you can set how far, how large, and what direction the light source is coming from. The settings in the window below seem to work well for me.



I'll go over the options a bit: Light Type- spotlight and point light I think are pretty self explanatory just manipulate the controls in the preview window to scale/move the lightsource, but directional light is essentially an ambient light whose direction and intensity you can change by moving and scaling the light line in the preview window. Intensity is just how bright your light is. Focus controls how sharp or spread out the light is. Gloss controls how much light gets bounced off the surface (in this case matte is better for a rock texture, but for instance if the rock was wet shiny might be a better option.) Material- I think for a rock more metallic rather than plastic is better. I havent found much use for exposure yet so keep it at zero. Ambience controls how much light there is in the scene besides your spotlight/pointlight. And height controls how exaggerrated the peaks and valleys in the rock are.

Now you could leave it at that and this is the texture you'd get:



A fairly smooth but somewhat bumpy rock. However let me go back to modifying your heightmap. If you wanted to create a more irregular rock texture, either undo the lighting effect you just did, or open your previous save (right after you faded the noise), and apply difference clouds to your heightmap again or a number of times more. The following used a heightmap with difference clouds done 4 times over:




Don't go overboard though otherwise it'll stop reading as rock, like this pic which is done 10 times over:



You can also go directly into your heightmap and paint things into it like I did with my skull here:



The only problem I'm having now is that there are so many different combinations of rocks that you can create by fiddling with all the settings, that my scene I think is looking a bit inconsistant. I greatly suggest noting down all the setting combinations you have and what type of rock they create so that you can recreate similiar types of rock later. Hope this helps!