● Create a procedural Stone texture (No UV’s)
● Easily convert it to Marble and give it a tint.
● Fundamentals of Art
● Fundamentals of Textures
That’s a pretty big claim isn’t it!? I was considering backing out of that claim pretty early but I think we’re all reasonable people here. I think we know this is going to be about fundamentals with a rock solid example (sorry, pun intended) rather than a literal breakdown of every texture you could possibly make! Though i’d quite like to see that tutorial too.
Not us!! Today we’re talking procedural texturing! That means whatever the shape of the object these textures should work.
Going to an image site like pixabay or cg textures is really handy if you can find the texture you’re looking for. Great for reference and if it’s seamless or you don’t mind spending the time making it seamless then why not use it on the model instead of all this procedural complexity?
Well I’m not saying don’t do that, photosourcing is still very useful and always will be, especially for grunge and other aspects of an image that you might want to add in.
Doing it without or with barely any photographs is an exercise in understanding and recreating the world around us allowing us to get a deeper appreciation. It’s a little like the same reasons for life drawing only for textures.
Then you have more control and ability when it comes to that moment when photographs aren’t going to help you out.
So what is that essence of art? What are those aspects of an image that we can control to help steer attention and make the statement as artists we want to make? Well there are quite a few, here’s just a couple of the most powerful ones….
Without contrast or color the focus or ‘point’ of the image is kind of unclear. With contrast we can draw attention to the foreground and separate it from the background. With color you can enhance and alter the mood even further.
So you can break down what’s going on in an image in many ways, here’s just some…
Ever looking for a way to enhance your art? Look through that list and make sure you have something to say about each one. Is there anything accidentally diluting the message or vibe of what you’re trying to communicate?
We can breakdown a texture in a similar way first by thinking about frequencies. In the same way audio can have low bass frequencies and high pitched frequencies so can an image.
If you haven’t seen this illusion before the idea is that close up it looks like Einstein and if you shrink it right down or move far away you’ll see it’s Marilyn Monroe. It’s the frequency of the images that give us the separation there. We’re looking at just the high frequencies of Einstein and the low frequencies of Marilyn Monroe.
Here are some other aspects of an image we can use to help breakdown what we’re looking at…
● Low Frequency
● High Frequency
● Weathering (Dirt/Scratches/Cracks)
● Highlights & Shadows
Let’s get to work and put all this into practice building a procedural stone texture. For building Cycles shaders you’ll find the starting blend file that I use here – Cycles Shader : Prime Elements. This gives me most of the things I find myself needing to create every time I start a shader. A tutorial with more information can be found here…
First up it’s that simple noise texture node with default settings going through a colorRamp node. The ramp is reducing contrast by having the lowest black level lighter and the highest white level darker therefore reducing the range. Note the vector information is coming out of the clean vector you’ll see more in the next image…
Note the distortion value i’ve highlighted with a white rectangle, we don’t really need the blur section here as none of those nodes are actually doing anything right now, in fact we could delete them. I have them here just in case. The little preview windows attached to the musgrave texture and the add node are showing what the musgrave texture is doing and how the texture looks so far.
For the high frequencies it’s pretty simple. That colorRamp just before the final node there is just to allow the highest frequency (noise scale 200) to pop out a bit more. Otherwise it’s getting lost in the brighter frequencies that are already there.
For some weathering detail like scratches, cracks and veins we can use the cycles crack group node from a previous tutorial. You can find that tutorial by clicking on the image. For a link to the required blend file click here.
TIP : I’m keeping it pretty simple in this tutorial however I would encourage you to add a high scale noise texture that breaks things up a little, also the resulting veiny pattern can then be used as a mask to drive some other lighter texture that is being added onto the texture so far.
So far the texture is just black and white, so putting that through a colorRamp node and remapping the greyscale to a color scale is what we want. Here i’ve just color picked from the stone reference image and then been careful to make sure the value figures (HSV setting) are roughly what they were before I color picked.
This section is a bit optional but should you be able to take advantage of it we can build up some dirt in the nooks and crannies. Plus we can create some worn looking edges too. For a model to take advantage of this it’ll need to have been modelled accordingly. That mostly means just having supporting edgeloops near sharp edges.
Also this is dependent on having 2 color sets though which you can see in the yellowy orange headed attribute nodes. The results of these are on the right of each half of the frame. The grunge is multiplied onto the main texture and the worn edges are added. TIP! As before with the cracks using these as masks to drive the balance between textures instead would crank the results up a notch here.
With the texturing basically finished we need to give this some effective shading. Here you’ll see a bump node going into the 3 normal inputs of the reflection frame. The colorMix node directly before the bump node is driving the height. The first socket is the low frequency and musgrave mix that we’ve already seen, and overlaid onto this is the second high frequency node set at a scale of 60.
One final touch is to take this and tweak it to serve as another similar surface. So here I’ve added a colorMix node which is overlaying green. The bump node is now doing nothing as i’ve unplugged all those goes into the normal sockets. Then i’ve cranked up the reflection settings. Both the amount of fresnel that’s going through and the overall amount of reflection. This is done by increasing the brightness of the first socket on the colorMix node right before the mix shader. TIP! Rather than just a single color giving a uniform distribution across the object try putting a noise texture through here to add extra variation!
For reference textures try pixabay
Image Based Lighting free HDRi archive HDRLabs
If you manage to create any cool procedural textures, please let me know! Many thanks! – Aidy. 🙂
This tutorial makes use of some audio from here..
Scratch : https://www.freesound.org/people/Raccoonanimator/sounds/160909/ by raccoonanimator
“Who Likes to Party” Kevin MacLeod (incompetech.com) Licensed under Creative Commons: By Attribution 3.0