Inside a Material 01 - Rusty Pitted Iron

[Traveler]

Inside a Material 01 - Rusty Pitted Iron

Instead of just posting some of these materials I figured why not start sharing some of the thoughts and techniques behind how they are put together. This time around we will look at this Pitted Rusty Iron material I have made. This will be an ongoing series of tutorials on unlocking the power of the material room!


NOTE: All renders are using Poser default lights and Final Quality automatic render settings

Render of the created material

Material Node Set-Up

First I started by adding the Clouds node. I am using this as the basis of my material. I switched the colors to those shown below.

Now I wanted some rusty looking spots on the surface, so to add this, I created the granite node and fed it into the cloud color socket. This makes the cloud part of the Cloud node take on the qualities of the Granite node. I have the granite the rusty colors, as well as made the scale larger to make it "Chunkier" and I made the shades 12 to "soften" the spots.

Now, If I left it there, it would be a good material, but there are a few more tricks that I can use to beef it up.

Next I added the fbm node. This will get a little work out as I am going to use it for coloring as well as a modifier to some of the other nodes!
In this case the fbm node becomes a "variable source" for the cloud node. So instead of taking an steady static scale and complexity value, it will look to the fbm node to supply the value, which will range from 0 to the value set in the cloud node's scale box for instance. Basiclly instead of the scale in the cloudes always being 12, if you plug the fbm node in it adds more interest by using scales from 0 to 12 depending on the value of the fbm node at any one point



Now, I want to add some scale changes in the clouds, otherwise they get a bit bland. So I hook the fbm node into the scale socket of the cloudes node! This means that the scale of the clouds is being controled by the fbm. I also set the scale up to 1.5 to take advantage of the greater range of scales.

Next I plug the fbm node into the sky color on the clouds node. This gives the material another layer of detail.

As you can see, I also plugged the fbm into the complexity of the cloud node. This adds variation to the complexity of the cloud base, which makes the material look even more real.

Again... if I stopped there it would be a good material.
However I want to more effects.... bump and specularity.
For both of these I need a greyscale map. To make any color node or map greyscale all you need to do is feed it though a Math_Functions node. (Which you can also use to adjust the balance of the greyscale map)
Since I want the shine and bump based on my rust map I simply plug my cloud node into the Math-Functions node which gives me a greyscale version.



I need it a little more dark then what the default "add" Math Argument gives me so I switch to Multiply and change the values until I am happy.
I then plug the Math_Function node into the bump socket.


The final step is to plug the Math_Functions node into the Specular value. (I set the highlight size to 0.1) I chose the normal specular here because I was looking for a duller kind of mat shine.


This makes the material the shinest when the rust is not. ((If you look at the map you can see that the dark areas are the same places where the rust is heaviest on the color map))

Close Up Render of Material

Lets say you wanted to use some of the alternate specularity options over the default specularity.... You would simply change the normal specular color to black, set the spec value to 0, and the highlight size to 0 (Yes this is necessary) Then I would set up the alt specular as I needed it. For example, here is the same material using the Glossy alt specular node:

Node Set-Up of the Above

The other types would either give me results that were not to my liking or were the same/close to what I have.

Blinn: Is best for softer highlights that are spread around and over the surface: ie skin


Ansiotropic: best for wet or slick looking highlights


Glossy: For super shiny or wet objects


Phong: Similar to the normal specularity, but it will give you a normal forward option and seems a little softer


Specular: Gives you a roughness option, and seems to be a similar varient of the normal specularity option

Here it is with the Specularity node pluged into the Alt Specular
- Not much of a difference

One more tip, LOL You can use the normal specularity and the alt specularity options at the same time, for a nice specularity sandwich. So say you wanted something that was shiny (normal specular) plus the nice soft qualities of the blinn, you would set up your normal shine settings and then also use the blinn plugged into the alt specular socket, giving you the effects of both

This render uses both Blinn and normal specular

[romax]

Thank you so very much!

[gini]

Thanks for this tut. Its a great base for experimentation. I've never set up shaders on my own before now.
More please, maybe one on fabrics (a variety of wovens ie cottons, linens, satins, sheers like chiffon or net ) leathers, and other types of surfaces, or just more on metals perhaps ?
Based on this tut I'm trying to get a corroded and distressed copper with touches of verdigris ..but not quite there yet.

[76claudia2205]

Thank you very much for making this so clear and understandable.
I am looking forward to the other series you have planned for us.
This is very cool!!!!